VT-x/AMD-V enabled but is not operational

[PeterNosko]

I'm running OS X 10.7.5 on a late 2007 Mac Pro.

I had no issues running VirtualBox under version 4.2.8, and unwisely allowed an update to 4.3.4. That caused my Windows7-64 VM to fail (bluescreen) right after startup and unsuccessfully attempt to repair itself.

SInce I didn't have any data on the VM, I decided to start completely from scratch. I ran the uninstall script for both versions and manually deleted my VM machines folder and the ~/Library/VirtualBox folder. I then did a fresh install of 4.2.8 and created a new Win7-64 VM. But when I try to start it up to install from the Window7-64 install CD, I get this error and can't find a way around it.

VT-x/AMD-V hardware acceleration has been enabled, but is not operational. Your 64-bit guest will fail to detect a 64-bit CPU and will not be able to boot.

Please ensure that you have enabled VT-x/AMD-V properly in the BIOS of your host computer.

Please help.

[mpack]

Go into VM settings and make sure the OS type is Win7-64bit, not just Win7. The old VBox didn't much care that you selected a 32bit template for a 64bit guest, but the new versions do care.

[PeterNosko]

Thank you so much for the reply.

Yes, it is. I used Win7-64 for the machine name, and it automatically selected "Windows 7 (64-bit)" for the type.

I deleted everything and tried once again. The attached log is from a single attempt to start the newly-created machine.

EDIT: Min Info follows

VirtualBox 4.2.8 r83876
Host: Mac Pro (late 2007), 2xQuad Core, 16GB
Guest: Win7-64, 1 CPU, 2GB (will install GA if I can complete the setup)

[mpack]

That's odd... the error I see in the log is different from the one you reported.

00:00:05.258488 HWACCM: VMX setup failed with rc=VERR_VMX_IN_VMX_ROOT_MODE!
00:00:05.258503 HWACCM: Last instruction error 0

This error means (I believe) that VT-x is already in use. Do you have another VM platform running, or system level debugger? Have you made sure that VT-x is enabled in the host BIOS?

As far as I know this error message is unrelated to the VBox software update.

[PeterNosko]

This error means (I believe) that VT-x is already in use. Do you have another VM platform running, or system level debugger? Have you made sure that VT-x is enabled in the host BIOS?

As far as I know this error message is unrelated to the VBox software update.

I have no other VM platform and I don't even know how to access the BIOS in my Mac Pro. But you made me realize that I hadn't rebooted in months and apparently there was a process running in the background because a reboot solved this!

I decided to retry VirtualBox-4.3.4-91027-OSX, but I had a repeat of another issue (that I mentioned in my first thread) where the VM would crash during the Windows install (where it was prompting for user and machine names). So I once again deleted everything, rebooted and reinstalled VirtualBox-4.2.8-83876-OSX. I now have a working Win7-64 machine.

THANK YOU!!!

[socratis]

apparently there was a process running in the background because a reboot solved this!

Just out of curiosity... Which process was using VT-x? Also, you are correct, you cannot easily access the "BIOS" (actually it's called EFI) on a Mac.

[michaln]

But you made me realize that I hadn't rebooted in months and apparently there was a process running in the background because a reboot solved this!

It's not necessarily a process. It's possible for something (some process) to change the VT-x state and then exit without restoring the initial state. When that happens, rebooting (resetting the processor) is the only safe solution.

[PeterNosko]

apparently there was a process running in the background because a reboot solved this!

Just out of curiosity... Which process was using VT-x?

Sorry, I really have no idea. All I know is that a reboot solved the issue.

[PeterNosko]

But you made me realize that I hadn't rebooted in months and apparently there was a process running in the background because a reboot solved this!

It's not necessarily a process. It's possible for something (some process) to change the VT-x state and then exit without restoring the initial state. When that happens, rebooting (resetting the processor) is the only safe solution.

Thank you, this is good to know.