I have a 64bit host, but can't install 64bit guests
Posted: 28. Jun 2014, 12:52
Note about VirtualBox 6.1.x and later. This topic has the name it has because that was how most users encountered the problem of VT-x/AMD-v hardware accelerated virtualization not being available. If the topic had been called "VT-x not available error" then newbies may not have understood the relevance. However VirtualBox since 6.1.x now requires VT-x/AMD-v to be available (or Windows NEM, but we'll leave that for now) for all VMs, whether 32bit, 64bit, single or multiple vCPU and so on. The original text remains below, the "bittedness" stuff is now less relevant, but the underlying problem and solutions have not changed.
VirtualBox requires hardware support for virtualization (Intel VT-x or AMD-v) in order to run certain categories of VM. This includes all 64bit VMs, and all VMs which use >1 CPU core. MacOS hosts require VT-x/AMD-v for every VM. Starting with VirtualBox 6.1.0 the latter is now true for all other hosts. The developers clearly feel that supporting older machines that don't have this hardware feature is no longer justified commercially.
To ensure that you can still run VMs in those categories, run through the following checklist :-
VirtualBox requires hardware support for virtualization (Intel VT-x or AMD-v) in order to run certain categories of VM. This includes all 64bit VMs, and all VMs which use >1 CPU core. MacOS hosts require VT-x/AMD-v for every VM. Starting with VirtualBox 6.1.0 the latter is now true for all other hosts. The developers clearly feel that supporting older machines that don't have this hardware feature is no longer justified commercially.
To ensure that you can still run VMs in those categories, run through the following checklist :-
- Note your exact CPU model or part number, then go online and check its capabilities. The CPU must be 64bit and support either Intel or AMD virtualization technologies: VT-x or AMD-v.
. - You usually need to enable VT-x/AMD-v in the host PC BIOS. You need to check with your PC manual or support forum to find out how to boot into the BIOS screen. This is probably not something we here at the VirtualBox forums can help you with. Once you get there you need to look for something buried in a menu, perhaps in the security category. The option may be called something like "Enable Virtualization Technology", "Enable SVM Mode" (AMD CPUs), "Enable Vanderpool Technology" (Intel), or perhaps "Secure Virtual Mode". If you see "Virtual Directed I/O" (VT-d/AMD-Vi) then that is a different thing. If you can find the latter option but can't find the former, and it's a recent PC (post 2016) then it's likely that VT-x/AMD-v is enabled by default in your BIOS, so go to step 3! Remember to cycle power on your host PC after making and saving the BIOS changes - in this case a full restart from power off is required, just rebooting or resuming from a hibernated state may not do the job.
. - If (1) and (2) are already taken care of, then make sure that no other host apps are already using VT-x/AMD-v. The usual culprits are system level debuggers, other VM platforms, and some resident anti-virus applications. This has become a particular issue with 64bit Windows desktop and server hosts - especially Win2k12, Win10 and later, as these may enable Microsoft's Hyper-v VM platform by default: this grabs ownership of VT-x and won't play nice with VirtualBox. Note: see the fourth post below for other Win10 functions that have this effect.
. - When creating a VM, make sure you choose the 64-bit version of the guest OS template in <VM Settings> | General | Basic | Version, e.g. choose "Ubuntu (64 bit)" and not "Ubuntu" or "Ubuntu (32bit)", otherwise a 64-bit guest OS may refuse to install. This has become more important since VirtualBox 4.3.x, because choosing the correct template also allows other modern processor features to be visible to the guest - it's not just about 64bit capability any more.