Disabling VT-X in VirtualBox (on Linux)

While trying to create a new Virtual Machine to install EBS on my home Ubuntu server, I received error messages saying “VT-X is unavailable (VERR_VMX_NO_VMX)” upon booting the new VM. This error message makes sense ┬ábecause my home server uses an old Core2Duo processor that does not have VT-X extensions.

In the VirtualBox GUI, however, the extensions tab where this feature could be disabled was greyed out (presumably due to my processor’s lack of the feature).

At first, at the recommendation of the top pages on google for the error message, I tried modifying this line in VM’s my .vbox file:

<HardwareVirtEx enabled=”true” exclusive=”true“/>
to:
<HardwareVirtEx enabled=”false“/>

When I restarted the virtual machine, however, the file would change itself back.

While it’s not very well documented, rather than editing the configuration file, it is a better idea to issue the following commands (replace EBS with your VM’s name):

VBoxManage modifyvm EBS –hwvirtex off
VBoxManage modifyvm EBS –vtxvpid off

These commands will use the VBoxManage command to properly change the configuration file and allow the VM to boot without VT-X extensions.