VirtualBox FAQ

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VirtualBox FAQ

Postby Forum Moderators » 13. Aug 2008, 20:01

VirtualBox - Frequently Asked Questions

You can use your browser's find option (typically Ctrl+F) to search here. Use single keywords as much as possible. Questions are now in different catagories. Click on the link below to go to the catagory directly.

General

Installation

Peripherals (keyboard, mice and video)

Network Related

USB Issues

Storage

Something to add, or need help?

Advanced Platform-related questions
Last edited by mpack on 27. Feb 2013, 19:00, edited 4 times in total.
Reason: Fixed broken links
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General Questions

Postby Forum Moderators » 26. Aug 2008, 21:06

General Questions about VirtualBox.

Q: I just signed up to the forums and it asks me to fill in the VB version, which one do I pick?
A: If you have Linux, you have two options: the OSE (Open Source Edition) and the PUEL (Personal Use and Evaluation License) version. When you download VB from the website then you have the PUEL version. Install the one from the repositories of your distribution, you have the OSE version. It's also in the name of the package you install, making it easier to spot the difference. Options to pick: Almost all of the choices apply. Only pick the OSE version that matches your distro. E.g. it would be strange to run Debian, but have the OSE from Fedora.
Windows and Mac users generally don't compile it themselves so they grab the PUEL version from the website. Options to choose: OSE Self-compiled or PUEL.

Q: When I start my VM, I get an error stating that no boot medium was found. How do I solve this?
A: Please read more about Virtual Machines so you know what VirtualBox actually does. Basically it comes to that it 'simulates' a computer with hardware and everything. The Guest does not know about the Host or it's hardware. So you have to install a seperate Operating System in it before you can really use VirtualBox.
Also make sure that if you want to boot from a CD/DVD or ISO, that it actually is bootable.

Q: When use the 'Check for Updates..." function in the GUI it says that I'm running the most recent version of VirtualBox, however if I check the download page there is a newer version. Why is this?
A: We deliberately delay the update notification a little bit, to give us time to sort out potential download server problems. After one or two days you will get the expected result.

Q: I keep getting the message about a new version, but I prefer not to upgrade. Can I disable this?
A: Open the generic VB preferences from the main window and disable the automatic update check.

Q: Does VB support 64 bit guests?
A: Support for 64 bit guests was introduced at version 2.0.0. If you wish to create 64 bit guests then we recommend that you upgrade to the latest version. Note that VirtualBox also supports 64-bit guest operating systems, under the following conditions:
  1. You need a 64-bit processor with hardware virtualization support (see User Manual chapter 1.2, Software vs. hardware virtualization (VT-x and AMD-V), page 10) and a 64-bit host operating system.
    NOTE: Since version 2.1.0, you can run 64 bit Guests while running a 32 bit Host. The prior requirement for Operating System is only for version 2.0.x. You still need the proper hardware.
  2. You must enable hardware virtualization through your BIOS; software virtualization is not supported for 64-bit VMs.
    Note: some HP BIOSES have a glitch, When You ENABLE VT-X/AMD-V, You DISABLE it, so do try both ways.
Q: I run a 64 bit Host OS, which version do I need?
A: You need the same kind program build as your Host OS. If you run for example Vista 64 bit, you need the 64 bit build of VirtualBox. If you run a 32 bit OS on your 64 bit CPU, you cannot use the 64 bit build. If you have an Intel CPU and run a 64 bit Host, pick the AMD64 package.
Also note that 64bit guests are not currently supported on MacOS.
Since 2.2.0, both builds are in the same installer for Windows Hosts, so you don't have to guess which build you need.

The reason you need to pick the AMD64 package, despite you having an Intel CPU, is that Intel has bought a license from AMD to be able to get the same 64 bit extensions in their CPU. AMD was the first one with 64 bit extensions in the CPU, and for compatibility Intel uses that now too. Therefor, all 64 bit packages you might need, are called AMD64.
Intel did have it's own 64 bit implementation, but was quickly dropped after obtaining a license from AMD. This is found in Intel's Itanium processors, codenamed IA64.

A common misconception about 64bit hardware: Having 64bit hardware/cpu does NOT mean you have VT-X/AMD-V as well, in other words: yes you can run a 64bit OS on 64bit hardware as a HOST, but a 64bit GUEST NEEDS VT-X/AMD-V to be active and enabled.

Also make sure another virtualizer isn't installed or running like KVM or Hyper-v. See also, click here.

HowTo: determine if VT-X/AMD-V is really activated and used by VirtualBox.

Another hint: after enabling VT-X/AMD-V in the BIOS you might need to switch the PC off completely, unplug it, or remove laptop battery for a minute. Ea:
Reboot the Host and go into the BIOS
disable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
start the Host and go into the BIOS
enable vt-x, save BIOS settings, pause machine after bios boot messages
power down the Host (unplug power cord!)
Boot the Host.

Q: I got my dual boot Windows XP running in VirtualBox using RAW Disk access, but I keep getting one core fully loaded. How do I solve this?
A: First, boot to your OS running on bare hardware.
  • Make a copy of \windows\system32\hal???.dll and \windows\system32\ntkernl???.exe to whatever names you want.
  • Change the processor type in hardware profile to ACPI single core. Do not reboot, but copy the new \windows\system32\hal???.dll and \windows\system32\ntkrnl???.exe to whatever names you want.
  • BEWARE, all his names must be 8.3 based.
  • Switch back to ACPI multicore - although this is not striclty needed, but in case in the future you do something wrong with your boot.ini, at least the default-named HAL and NTKERNEL will be there.
  • Change your boot.ini to have two systems to boot (basically duplicate the existing one, change the name) and add the /KERNEL and /HAL options - here is an example:
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    [boot loader]
    timeout=30
    default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
    [operating systems]
    multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP (multicore)" /fastdetect /NoExecute=OptIn /kernel=ntkrnlmp.exe /hal=halamp.dll
    multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP (singlecore)" /fastdetect /NoExecute=OptIn /kernel=ntkrnl.exe /hal=hala.dll
  • Now by default, boot.ini is a hidden file on the root of the C: drive. There are several ways to open this file. Either change your Explorer settings to show hidden files and folders. go to System Properties tab Advanced and hit the Settings button on Startup and Recovery. Now you can use the Edit button to edit the file. A different method to use, is open a command prompt, go to the root of the drive and type notepad boot.ini.
    There is a high chance that you can't save the file because it's read only. Change the file properties from Explorer or run
    Code: Select all   Expand viewCollapse view
    attrib -h -s -r c:\boot.ini
    notepad c:\boot.ini
    attrib +h +s +r c:\boot.ini
    from the command prompt.
Now it works, you have multicore in native and no more 50% CPU usage in Linux+VB when you choose the single core HAL/NTKERNEL. The tradeoff is that when you boot, you have to press 2 or 3 keys before the computer actually boots (choose Linux/Windows, then in Windows Multi/Single core the the Hardware Profile).

Credits for this information to Philippe.

Q: Why don't you make VirtualBox so it can run without a Host OS like VMware ESX?
A: VMware ESX, like Xen, is a type-1 hypervisor, also known as a bare-metal hypervisor, meaning that it's a "thin" OS that only does basic functions, like managing hardware resources and controlling the Virtual Machines.
VirtualBox, like VMware Workstation/Fusion, is a type-2 hypervisor, also known as a hosted hypervisor. It's an application that runs above an existing OS, which in this case is the one that manages the resources.
Sun Microsystems is already working on it's own type-1 hypervisor, named xVM Server.

Q: I am running Linux and my kernel has just been upgraded. Do I need to do anything?
A: VirtualBox links its device drivers against the kernel during installation. The drivers link into addresses inside the kernel. The correct addresses may change when your kernel is upgraded, and as a result VirtualBox can start to cause otherwise inexplicable errors. After kernel upgrade it is always sensible to relink your kernel drivers. This is by running vboxdrv with the setup option. The command that you will therefore typically run is sudo /etc/init.d/vboxdrv setup. If you install the DKMS package, all kernel modules are installed automatically when you install a new kernel.

Q: So is VirtualBox based on QEMU?
A: No, VirtualBox is independently developed. It does use QEMU for some real-mode execution (when using Software Virtualization) and for emulation of certain more complicated instructions (when in Hardware Virtualization VT-x/AMD-V mode). But this accounts for a tiny fraction of the time a typical session runs.

Q: I want to use more than one processor in my VM, but I can't move the slider. Why is this?
A: You need hardware virtualization in order to use SMP (multi processor support). The same requirements are in order as for running 64 bit Guests. AMD-V/VT-x need to be available in your CPU, your motherboard needs to support this and it needs to be enabled in your BIOS. I/O APIC and ACPI are also needed. More information can be found in the user manual, chapter 3.7.2.2.

Q: I want to move my VM to a different host, how do I do that?
Q: I want to share my VM with my dual-boot, how do I do that?
A: The VDI need to be on a shared location so both OSses can read and write to the file in case you want to share it between your dual-boot Host.
Create a new VM on the other system, select the VDI from the first Host as hard drive instead of creating a new one and make sure that every setting is exactly the same. The MAC addresses of the virtual NICs also need to be the same, to avoid possible Windows activation prompts and new interface names on Linux.
For Windows 7, there is one additional step that needs to be the done to avoid reactivation. The VM UUID need to be transferred from the original VM to the new one. Open the XML file of the original VM and copy the UUID and transfer that to the new VM XML file. Look for this line at the start of the file:
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Machine uuid="{075d42da-6025-4a95-a1d5-57b1f4b09dd7}" name="Windows 7" OSType="Windows7"

The 'hash' in curly brackets is the UUID you need to copy and replace in the new VM XML. This change is not yet done, because the VirtualBox.xml file doesn't know that UUID, it still holds the old UUID of the VM. Open the VirtualBox.xml file in a text editor like with the machine.xml file and look at a line that looks like the following and replace the UUID.
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<MachineEntry uuid="{075d42da-6025-4a95-a1d5-57b1f4b09dd7}" src="/media/Extern/Virtual Machines/Windows 7/Windows 7.xml"/>

The src= line is how you can spot your VM. The actual location of the XML depends on the Host and configuration of the VM location. By default it's in the user profile folder.
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Installation Questions

Postby Forum Moderators » 26. Aug 2008, 21:07

This post is about Installation Questions.

Guest Additions are also known as GA.
CLI Command Line Interface.
OSE VirtualBox Open Source Edition (OSE).
PUEL VirtualBox Personal Use and Evaluation License (PUEL).

Q: VirtualBox prompt me with a warning about it not passing Windows logo testing
A: You can safely ignore it and continue installing. If you stop the installation, VB will not work properly.

Q: I can't select a higher resolution than 800 x 600, how can I get higher resolutions?
A: You have to install the Guest Additions inside your Virtual Machine. See the manual for more information about the GA. Make sure you also have Auto-resize Guest Display enabled in the Machine menu (shortcut Hostkey+G).

Q: How do I install the Guest Additions in Linux Guests?
A: See the Howto: Install Linux Guest Additions for an extensive Howto. In addition, there is a Shared Folders howto too.

Q: I upgraded from >= 1.5.x to a newer version and now my Windows Guests keeps booting with a BSOD.
Q: My XP VM from a previous version/installation keeps getting a BSOD when booting, but I'm pretty sure the settings are correct.
A: Check your VM settings. Go to General, tab Advanced and make sure that the IDE Controller is on PIIX3 and not PIIX4. Now boot your VM.
In newer versions of VB, this option might be somewhere else. Since 3.1.0, the whole storage system changed and the controller type is now listed as it's own property.

Q: What is the proper way to upgrade?
A: Since version 1.6.0, you no longer need to uninstall VB in Windows, but can install it on top of the current installation. This can be done by running the installer and follow the on screen instructions. For Linux Hosts, just run the install file (.dep, .rpm or what package manager you use) as root. The package will be updated automatically. For other systems, it should be the same procedure. The one exception to this is due to naming clashes: you do need to properly remove an OSE package if you are replacing an OSE version with a PUEL versions (for example because you need USB support).
All VMs are kept during the upgrade or when you uninstall VB.

Moving to a new major version can be problematic too for Linux users. If you want to upgrade, fully remove the old version and then install the new one. It is advised to purge residual config, but it is not mandatory. For Debian based systems, this can be done using the following command (or use Shift+Del in the package manager for complete removal):
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sudo apt-get remove --purge virtualbox-2.0
sudo apt-get install virtualbox-2.1
Same goes for the upgrade to newer major releases, like 3.0, 3.1, 3.2, 4.0, 4.1, etc.

Q: Can I run Mac OS X as a Guest on VirtualBox?
A: Yes, but there are strict rules to follow. Apple's End User License Agreement (EULA) states that Mac OS X must only be installed on real Apple hardware. Only Mac OS X 10.5 Server's EULA states that one copy may be installed on Apple hardware, even if virtualized.
To read Apple products EULA, please refer to their legal page at http://www.apple.com/legal/sla/.
This means that you can run OSX Server ONLY on a Mac. If you have a PC, you can't run OSX Server as Guest. The EULA clearly states that only the Server version may be virtualized, so don't bother with the Desktop version. Asking it here won't get you anywhere either.
More about this can be found here: Important notice regarding Mac OS X as Guest.

Q: Where can I get just the guest additions?
A: The Guest Additions are shipped with the installer, so you don't need to download it separately. However, there are times when you may need just the guest additions. You can download an .iso with the guest additions from the download site: http://download.virtualbox.org/virtualbox/. For example, version 2.1.2 of the guest additions are available as:
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http://download.virtualbox.org/virtualbox/2.1.2/VBoxGuestAdditions_2.1.2.iso


Q: I get an error when I try to install the Extension Pack. How do I solve this?
A: This depends on the actual error you get. Here are some possible solutions for the different error codes. The fix is not guaranteed to work.
Windows:
- Error 128: Install .NET Framework 3.5 and it's updates, then try again.
- Other: Make sure you run VB as administrator first before installing the ExtPack. Windows Vista and 7 users should get a UAC prompt when VB is run as normal user and try to install it, if UAC is enabled.
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Peripheral Questions (Mice, Keyboards and Video Cards)

Postby Forum Moderators » 26. Aug 2008, 21:07

This post is all about the peripherals Keyboard, Mice and Video Cards.

Q: I just installed my Guest, but the screen won't go bigger, how do I do this?
A: You need to install the Guest Additions before you can use high and custom resolutions in the Guest.

Q: I installed my ATi/nVidia/... videocard in the Guest system, but I can't select higher resolutions, what's up?
Q: I tried running Compiz Fusion / Aero on my guest and I got an error, what's the problem?
Q: I tried to play a game that requires DirectX / Direct3D / OpenGL and it doesn't work, what should I do?
A: VirtualBox simulates a basic VESA adapter, so your Guest has no access to the advanced features of your videocard. This includes everything that has something to do with 3D acceleration, including the Special Effects of Compiz on Linux. DirectX dependant games will not run.
NOTE: Since VirtualBox version 2.2.0, Linux Guests can use OpenGL. You do need a Host that is capable of OpenGL. Most Intel onboard graphics are not capable of OpenGL on Windows Hosts, and use Software Rendering in Linux Hosts.
Also, if you use OpenSource drivers on your Linux Host, Hardware Acceleration is probably not (yet) available.
Since version 3.0.0, DirectX 8 and 9 are also available, though limited. The implementation is based on the WineD3D libraries and code, and therefore not fully functional, some features are not available. Don't expect to run all DX8/9 games inside VB.

Q: Why doesn't my mouse get grabbed by the Guest?
A: Start your VM, click inside the VM window space and tick the box on the warning, then hit the 'OK' button. Now next time you click inside the VM, it will be grabbed automatically without further questions.

Q: I got Windows 9x running, but I can't get sound/video to work properly.
A: Please see the Tutorial: Windows 95/98 guest OSes from Technologov for this.

Q: I enabled 3D in my VM settings, but my Guest gives some errors when enabling OpenGL acceleration. I do have the Guest Additions installed.
A: Check your video card. It must support OpenGL and have the correct driver installed. If you run Linux as host, not all Open Source drivers support 3D acceleration yet.
A special note need to be taken for Intel video cards. Most of them don't support hardware accelerated OpenGL. Most of their cards so far only work with DirectX, which VB doesn't support for Guests as direct acceleration (yet). So enabling 3D won't have any advantage if you have an older Intel card. It's best to check the Intel website for technical specifications of the video card to see if support is available. Current generation Intel cards DO have proper OpenGL acceleration capabilities.
Another note for Windows Guests and DirectX, the Guest Additions MUST be installed in safe mode for 3D to work properly. System files are replaced and will be restored when installing in normal mode, causing the 3D options to be broken.
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Networking Questions

Postby Forum Moderators » 26. Aug 2008, 21:07

This is all about Network related Questions.

Q: My Guest doesn't see my wireless network, why is that?
A: Please read more about Virtual Machines so you know what VirtualBox actually does. Basically it comes to that it 'simulates' a computer with hardware and everything. The Guest does not know about the Host or it's hardware and therefore not able to see your wireless adapter.

Q: I set up a bridge with my wireless adapter, but it doesn't work. My Guest does not get an IP address or access the internet when I manually set one.
A: Creating a bridge with a wireless network card does not work. This is because of the limitations of the current bridge functionality. Please use NAT for Internet on the Guest system, or use Internet Connection Sharing to the virtual Interface without the use of a bridge.

Since 2.1.0, you can select the NIC directly. Wireless will work with this. Though not all wireless adapters support the first option VB will use when accessing the network, and that is changing the source MAC address. VB will fall back and use the physical MAC address to get network access. Some DHCP servers keep track of these MAC addresses with their lease table and deny a new IP address if the MAC is already linked to an IP.

Q: I switched from VMWare and now my network doesn't work.
A: Remove the VMWare Tools first. VMWare includes custom drivers for the network interfaces and they don't play nice with the interfaces VirtualBox emulates.

Q: I have set up a VM with NAT networking, but it can't access internet while my Host system can.
A: NAT only translates TCP or UDP. One of the common reasons is that your task requires another IP protocol; for example ping relies on ICMP which is not translated. Some VPN protocols also use GRE which is also not translated.

Another common issues is that the DNS relay within the VirtualBox VMM only forwards all DNS queries to the first configured DNS server known to the host and does not search the entire DNS server list. If this DNS server is offline the hot will fail-over to the second server on the DNS list, etc., but the guest will effectively loose DNS. You can test this by checking to see if you can browse by IP from the guest (e.g. http://66.102.9.99/ gives you google) then it is a DNS problem. To avoid this problem you need to manually configure DNS on your guest OS. In the case of Linux guests see Can't connect to the internet for further discussion.

In the case of a Windows Host, also look at your firewall. There are some firewalls that block the transient packets from VB. The following firewalls are reported to block them:
    Agnitum Outpost Firewall Pro
    Kaspersky Internet Security
    ESET Firewall
    Avast 4 Home (when installed on Guest, whole network seems to stop, also on Host. See this topic)
For Outpost, there is a work-around. Change the firewall policy according to the following:
1- Open the program preferences.
2- Select Application Rules and browse to VirtualBox.exe
3- Click on Modify.
4- select the Options tab.
5- Deactivate the Content Filtering.
Thanks goes to moody_styley

Q: I want to make my Windows guest a member of a Windows domain. Can I do this?
A: Perhaps the simplest approach is to use a bridged network. However, at least one member has reported getting this working with NAT. See Windows XP and Active directory GPO for more details.

Q: I (accidently) cancelled the installation for the Host Interface on Windows Host and now I have a device in my Device Manager that I can't remove. How can I remove it without reinstalling my Host?
A: Open your Device Manager, right click on the device and select Update/Reinstall Driver. Now select to look for a driver manually, then select that you have a disk and point to the driver yourself. Click on the Have Disk button and browse to the VB installation folder. In there, you will find the driver for the Interface. Continue the installation this time and it should install properly. You can now remove the device if needed.
Thanks for pjmlp in VirtualBox creates unremovable network drivers for the information.

Q: I use >= 2.1.0 on Windows/Linux and I can't find the "Add Interface" button, how do I use Bridged Networking (Host Interface)?
A: You no longer need virtual interfaces. You can select the NIC directly. If it's not shown in the list of interfaces to use, the driver/module isn't installed/loaded.

Q: I use >= 2.1.0 and want to use the old Host Interface method, how can I do this?
A: You have to create virtual interfaces and bridge them like you used to do. Linux has the TAP interfaces you can create with the uml-utilities package. For Windows, please see MS KB839013 - How to Install the Loopback Adapter in XP for more information. Vista users should have the same method, but if you don't, please look for other ways, like using DevCon.

This is about vRDP and RDP:
vRDP: A VBox method that lets you connect to the VM screen, mainly suited for Guests that do not have any RDP support, or to control a Guest that has no other remote control features.
RDP: A Windows integrated standard to remotely access a windows Guest.
  1. When running a VM you usually see a 'smaller' screen on your desktop where the Guest is running in, it is THIS screen you access when using vRDP, vRDP has absolutely NO relation to the Guest or what its doing, it simply allows you to control a Guest via remote.
  2. RDP is a typical Windows thing, however there are many other RDP implementations for linux, mac and others, both as RDP server and client(s).
  3. For example when a RDP sessions aborts or runs into a problem where your RDP sessions doesn't work anymore you could access the VM Guest via vRDP since vRDP is a VBox thing (when enabled in the Guest settings).
  4. vRDP happens to be pre-configured to use the SAME port as RDP does, 3389, which is why the both are easily confused with each other.
  5. vRDP works 'out of the box' since it connects directly to the VM screen, RDP does not since it needs to connect directly to the Guest either via a port forward (see the Manual) or via the Guests IP address when using Bridge mode.
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USB Questions

Postby Forum Moderators » 26. Aug 2008, 21:08

All about USB related Questions.

Q: I installed VirtualBox from my distributions repositories and I can't access my USB devices or see an option to enable USB.
A: Since VirtualBox v4.0.0, USB 1.1 support is included in as standard. In order to get USB 2.0 you have to install the "Extension Pack" found on the downloads page. USB 3.0 is not currently supported.
A: (Older VirtualBox versions) You must install the PUEL Edition of VirtualBox. The OSE version does not include RDP, USB, iSCSI and SATA support. See the Wiki Editions page for an explanation of the differences between the two VB versions.


Q: I connect an USB device, but it isn't grabbed by the VM. What's going on?
A: Have you installed the Extension pack? See the discussion above if not. Otherwise read the Wiki and manual for how to set it up in Linux Hosts. Windows systems should work automatically. There will be a question for a driver on the Host once VB grabs it. Continue the installation, letting it search for a driver automatically. If you get a prompt about driver signatures, just Continue Anyway.

Q: I get an error stating "Could not load the Host USB Proxy Service (VERR_FILE_NOT_FOUND). The service might be not installed on the host computer."
A: Since VB 2.2.0, you should no longer need to change anything to your config. There are new udev rules for VB that will take care of this. Before changing any system settings, check with a VM if you already have access to USB devices.
Just make sure you are a member of the vboxusers group.


If the above group membership doesn't help, try the following:
For Ubuntu, please see https://help.ubuntu.com/community/VirtualBox#USB for how to fix this.
Ubuntu 8.10 users should check http://ubuntuforums.org/showpost.php?p= ... ostcount=2 for the new fix.
Fedora and CentOS users should take a look at viewtopic.php?p=52746#52746
Other users can try the following in their fstab:
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none /proc/bus/usb usbfs devgid=118,devmode=664 0 0

Replacing 118 with the Group ID that vboxusers has. This can be obtained by viewing the group file in /etc or if you're already a member of the group with the command id

Note the devgid is the Group ID of the vboxusers group. You have to be a member of this group first. During setup, this is also asked. You usually don't have the ability to run VB if you aren't in the group, due to the kernel module access. You can check in which groups you are by opening a terminal and run id. If you're not a member of the vboxusers group, add yourself with the following command with root privileges, then log off and back on.
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usermod -aG vboxusers <your username>

Note: The advice to mount usbfs to /sys/bus/usb/drivers which could be found in an older version of this FAQ is wrong!

Sometimes the above doesn't work either. If that's the case, open a terminal emulator window and use the following command, after which you start VB from the same terminal.
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VBOX_USB=usbfs VirtualBox
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Storage and the sort

Postby Forum Moderators » 26. Aug 2008, 21:08

Storage related Questions.

Q: How do I properly clone a VM?
A: Since VirtualBox v4.2.0 the procedure is simple. Just right click the VM in the VirtualBox manager window, and select "Clone".
  • The dialog box will offer the chance to keep old network MAC addresses or generate new ones. If you intend to run old and new VMs at the same time then you must generate new MAC addresses. Be aware however that this can cause network cards to be renamed, and Windows guests might have activation problems.
  • If the original VM uses snapshots then you will also be offered the opportunity to preserve the snapshot history, or only clone the current state of the VM.
Q: How do I properly clone a VM? (older VirtualBox versions)
A: First you have to clone the hard disk. Start by merging all saved states and snapshots if you want to have the latest changes in your clone. Once you've done that, just follow the Manual:
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VBoxManage clonehd <uuid>|<filename> <outputfile>
To use the clone VDI you must create a new VM, then when you get to the disk creation step you choose "Existing disk" and browse to the clone VDI. When creating a new VM it's best to use the same settings as your original VM.

Q: How can I resize the partitions inside my VDI?
A: For this, see this post in the Tutorial: All about VDIs: How can I resize the partitions inside my VDI?

Q: I want to make my virtual hard drive bigger, how do I do that?
A: Since 4.0.0, you can use
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VBoxManage modifyhd <UUID|file> --resize <size in MB>
to resize the max size of the VDI. You can only make it bigger. After that, use Gparted to increase the partition size inside the VDI.
A: (Older VirtualBox versions) You have to clone the data from the VDI you already have to a new, larger VDI and expand the partition(s). You can use tools like CloneZilla to clone the virtual hard drive to the bigger one, then use Gparted to increase the partition size.
A: (Unofficial alternative) Use mpack's CloneVDI tool to clone the VDI with a larger size. This tool can enlarge Windows partitions at the same time as enlarging the disk. For Linux partitions you would have to use Gparted as a separate step as above.

Q: How do I access Shared Folders?
A: You have to install the Guest Additions first. This is all described in the manual (and above for Linux), but as most users don't even read that, it will be pasted here. There is also a howto for Linux here.
  • In a Windows guest, starting with VirtualBox 1.5.0, shared folders are browse-able and are therefore visible in Windows Explorer. So, to attach the host’s shared folder to your Windows guest, open Windows Explorer and look for it under “My Networking Places” -> “Entire Network” -> “VirtualBox Shared Folders”. By right-clicking on a shared folder and selecting “Map network drive” from the menu that pops up, you can assign a drive letter to that shared folder. Alternatively, on the Windows command line, use the following:
    Code: Select all   Expand viewCollapse view
    net use x: \\vboxsvr\sharename
    While vboxsvr is a fixed name (note that vboxsrv would also work), replace “x:” with the drive letter that you want to use for the share, and sharename with the share name specified with VBoxManage. Note that you can still map a shared folder with NAT network.
  • In a Linux guest, use the following command:
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    mount -t vboxsf [-o OPTIONS] sharename mountpoint
    Replace sharename with the share name specified with VBoxManage, and mount-point with the path where you want the share to be mounted (e.g. /mnt/share or /media/share). The usual mount rules apply, that is, create this directory first if it does not exist yet. Beyond the standard options supplied by the mount command, the following are available:
      iocharset CHARSET
    to set the character set used for I/O operations (utf8 by default) and
      convertcp CHARSET
    to specify the character set used for the shared folder name (utf8 by default). The generic mount options (documented in the mount manual page) apply also. Especially useful are the options uid, gid and mode, as they allow access by normal users (in read/write mode, depending on the settings) even if root has mounted the filesystem.

Q: I get the error "PIIX3 cannot attach drive to the Secondary Master." when I start my VM. How do I solve this?
A: VB is not able to mount the CD for the VM. Release the ISO or physical drive from the VM settings. If you can't do that, edit the <machine>.xml file and remove the attached file/device. It looks like this, remove the line in the middle.
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<DVDDrive passthrough="false">
    <Image uuid="{4ea51667-6a4a-4954-b32f-855da6815fb2}"/>
</DVDDrive>

Newer versions of VB use a different syntax, which would look like this:
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<AttachedDevice passthrough="false" type="DVD" port="1" device="0">
   <Image uuid="{361e1c45-3136-4dcb-b358-08d771e2ee1c}"/>
</AttachedDevice>


Q: I get errors about disk space, out of disk space, disk full, but I have plenty of space left. How do I solve this?
A: Most likely you are using a disk partition formatted in FAT32, files on such partitions can not be larger than 4gb, convert to NTFS or other format.
Last edited by mpack on 30. Mar 2013, 15:09, edited 8 times in total.
Reason: Reflect changes in VirtualBox v4.x
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Getting Help

Postby Forum Moderators » 26. Aug 2008, 21:08

Have something to add, or need to file a bug report? Here is the info.

Q: My question is not listed here, what can I do to add it here?
A: Check if it isn't listed on the link below. If it isn't, open a topic and follow The Forum Posting Guide. More FAQs can be found on the User FAQ in the Wiki. If you already have an answer, note it too or you want to suggest a change, then please raise your point in Discuss Forum FAQ and we will see how we can add it here.

Q: How do I raise a problem report?
A: You need to register for a user account with the Trac system and this gives the links. Use VirtualBox — Select Trac Report and VirtualBox — Create New Ticket for reporting and creating tickets. See How do you log a new issue? for the further discussion. Please remember to make sure that your problem isn't related to an existing ticket (use the search trick: google <your keywords> +ticket site:www.virtualbox.org) before opening a new one.

More answers/solutions in the QuickClick FAQ
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Re: VirtualBox FAQ

Postby Forum Moderators » 17. Jul 2010, 02:19

Advanced Platform-related questions:

Q: Can VirtualBox run on Xen Domain-0 type 1 hypervisor host?
A: No.

Q: Can VirtualBox run on Hyper-V type 1 hypervisor host?
A: Yes, but at a big (20x) performance drop

Q: Starting Virtualbox in VT mode on some Toshiba Laptop hardware makes VBox crash. Why?
A: This is known crash for certain Linux host kernels. Workaround is to remove "toshiba_acpi" kernel module.
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