Can't change screen resolution on VM

[Pavel_167]

Hello,
Can't change screen resolution on Linux VM: all options are disable.
Where is the problem ?
Thanks.
Sincerely,
Pavel.

[scottgus1]

Guest Additions are needed for screen size changes to work

Installing Guest Additions in Linux VMs has prerequisites, same as for installing Virtualbox on the host, see https://www.virtualbox.org/manual/ch02. ... nux-prereq. Often the thing needed is the headers.

Then use the VM's Devices menu, "Insert Guest Additions CD Image" to insert the GAs ISO into the VM's CD drive, then run the installer.

After GAs install correctly, shut down the VM fully, enable 3D acceleration in the VM's Display settings, crank video RAM up to max, then start the VM again.

[Pavel_167]

Thanks.
There are still problem nevertheless:
- screen resolution that I specify doesn't correspond to what I see at the screen
- have 3 screens, connected to PC, but only for one screen changing resolution is available.
Sincerely
Pavel.

[scottgus1]

Start the VM from full power off, not save-state. Run until you see the problem happen, then shut down the VM from within the VM OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Please right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.

[Pavel_167]

Please right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.

Here it is.

[scottgus1]

There are still problem nevertheless:

Looks like there are still problems despite.

00:00:03.228190 VirtualBox VM 6.1.26 r145957 win.amd64 (Jul 28 2021 17:15:09) release log
00:00:12.417054 VMMDev: Guest Additions information report: Version 6.0.0 r127566 '6.0.0'

The up-to-date GAs did not install. The 6.0.0 Ubuntu fork GAs that Ubuntu distributes pre-installed in their OS's are too old.

[Pavel_167]

Well ... I downloaded "good" GAs .iso file.
But when I click Devices-->Insert GAs CD image, the Error message appears "Unable to insert the virtual optical disk
C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso into the machine Ubuntu64_VW"
Should I copy the downloaded GAs .iso file in the specified location and rename it ?

[scottgus1]

This is not necessary:

Well ... I downloaded "good" GAs .iso file.

The correct Guest Additions ISO comes with Virtualbox.

"Unable to insert the virtual optical disk
C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso into the machine Ubuntu64_VW"

There is probably more to this error message. Please post the whole message when posting an error message. Often there is a Copy button in the Virtualbox error box to facilitate copying the whole message to the clipboard then to the forum.

The rest of the message may have had something in it about VERR_PDM_MEDIA_LOCKED. This is common for VMs with Linux OS. It means there is already a "CD" in the VM's CD drive and Linux won't let go of it. In all likelihood you already have the GAs "CD" in the drive. Open the VM's CD drive inside the Linux OS. Are there Guest Additions installer files present?

[Pavel_167]

Here is error message:

Unable to insert the virtual optical disk C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso into the machine Ubuntu64_VM.

Could not mount the media/drive 'C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso' (VERR_PDM_MEDIA_LOCKED).

Result Code: E_FAIL (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}
Callee: IMachine {85632c68-b5bb-4316-a900-5eb28d3413df}

Open the VM's CD drive inside the Linux OS. Are there Guest Additions installer files present?

Here is contents of VM CD, opened in Linux:

[scottgus1]

OK, the error message and CD drive contents are as expected. The GAs ISO is already loaded and mounted by the Linux OS, so Linux won't let the same CD get mounted twice.

Run the prerequisites and the CD drive's Linux installer.

[Pavel_167]

Run the prerequisites and the CD drive's Linux installer.

From Linux terminal ?
What is the syntax of command ?

[scottgus1]

From Linux terminal ?

Yes.

What is the syntax of command ?

Try to figure it out with careful reading of the prerequisites first and web-searching how to run these commands in the Linux terminal, then let us know what you tried. If there is a problem, post the command tried and the error message result, and we'll see what can be done.

[Pavel_167]

Tried to search for "prerequisites" on the web.
In the only link that looks relevant, sounds like this:

Code: Select all

sudo apt-get install build-essential git swig python-dev python-numpy python-matplotlib python-h5py python-pillow

Probably there are other "prerequisites", but this one doesn't work: unable to locate some python packages.
Concerning installing CD are you sure that default Ubuntu installation doesn't already have all generic drivers for CD.
Moreover, I you saw I could open GAs CD drive (which is probably isn't compatible with current version of VirtualBox), but at least CD drive does exist.
What kind of CD drive you are talking about.
Anyway I googled for "ubuntu install CD drive"and found nothing relevant.

[scottgus1]

Tried to search for "prerequisites" on the web.

How about the Virtualbox manual prerequisites link I posted above?

Don't worry further about the CD drive. The picture above of your VM's CD drive has exactly what is supposed to be in it already, because the GAs ISO has been loaded correctly.

[Pavel_167]

How about the Virtualbox manual prerequisites link I posted above?

Sorry, I don't see any link.
Can you repeat it, please.