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Hello VirtualBox Community,

I am a new user and created my first VirtualBox VM (v4.3.28) yesterday! I learned that in order to run a 64-bit guest OS (in my case, Windows 7), I needed to enable Virtual Technology (VT) in my BIOS/UEFI. My host computer has an Intel i7-3770K and is running Windows 7 Home Premium (I do not believe I have Hyper-V). I set up my VM to snapshot, and it continued to turn on until after rebooting my physical computer. Now I receive the following error and no longer see 64-bit OS options in VirtualBox; my Settings>System>Acceleration tab is also grey:

Failed to open a session for the virtual machine <Name of VM>.

VT-x is disabled in the BIOS. (VERR_VMX_MSR_VMXON_DISABLED).

Result Code: E_FAIL (0x80004005)
Component: Console
Interface: IConsole {8ab7c520-2442-4b66-8d74-4ff1e195d2b6}

I found several posts about this, however, I ended up more confused than before. I have (1) checked VT is enabled after shutting down PC, (2) flashed my UEFI, defaulting its settings and re-enabling VT, and (3) set <HardwareVirtEx enabled="..."/> to false in both instances of my VM's .vbox file.

My VM was set to run 2 cores, 2 GB of RAM, and 256 MB of GRAM. If a log file is needed for assessment, please kindly let me know how to grab it. I am not sure which programs (other than Hyper-V) that might utilize VT and conflict, but I would be happy to confirm if I have X installed. Thank you very much for reading and in advance for any thoughts!



With regards,

Polite Master

The message means what it says.

I'm afraid we can't tell you how to enable VT-x on your PC, every PC is different so you need to look in the PC user manual, or contact the vendor.

Setting HWVirtEx to false in VirtualBox is not useful. It must be enabled for all 64bit VMs, and all Windows versions (including 32bit) of Win8 and later.

What mpack said. VirtualBox has no way of telling why VT/x is disabled, it can only see that it is disabled (and the CPU is designed such that it can't be enabled at that point).