kernel requires x86-64 CPU/VT-x is not available

[RobbieRobski]

I just upgraded from 4.2 to 4.3.x on Windows server 2008 host.

I have 2 guests(1 centos 1 custom) which worked previously (although they were test environments and not running full time)
now when I try to start those it says

Failed to open a session for the virtual machine AsteriskNow.

VT-x is not available. (VERR_VMX_NO_VMX).

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


I also tried creating a new VM and when I try to boot it up I get the message about kernal requiring X86-64
There is nothing under Settings>Basic>Type or Version which mentions anything about 64bit.

Hyper V is installed but not running.
If I try to VBoxManage modifyvm existingguest --longmode off

then I will get an error kernel requires x86-64

Should I just uninstall and get 4.2 again?

[Perryg]

Hyper-v doesn't even need to be "not running" unless you mean you have used bcedit to disable it. It loads at boot and takes the VMX flag so nothing else can use it.

[RobbieRobski]

I dont know what bcedit is. But since your post I have also uninstalled hyper-v completely and rebooted via powershell:
Import-Module servermanager
remove-windowsFeature Hyper-V.

But I still get this problem.

[Perryg]

Now that you have hyper-v removed I would put the guest back to its default settings.
If that does not help then post the guests log file ( as an attachment )

[RobbieRobski]

I am still getting the error. On both the original guest, as well as the new guest I tried to create. Here is the log on the new vm.

[Perryg]

Guest OS type: 'Ubuntu'

If the guest is 64-bit you need to select 64-bit in the guests settings version.

[BillG]

I dont know what bcedit is. But since your post I have also uninstalled hyper-v completely and rebooted via powershell:
Import-Module servermanager
remove-windowsFeature Hyper-V.

But I still get this problem.

I suggest you look in Windows Help for bcdedit (or bing or google it). How long have you been running Windows?

[RobbieRobski]

I realize I'm posting to a public forum asking for free help. But don't you think you're coming off a little pretentious thinking that someone asking for help should know everything; then asking me how long I've been using windows as if it's my first day and bcedit is just common knowledge?

I'm sure we've been using windows for roughly the same amount of time in different capacities between our different career paths. Never once had to know anything about bcedit. Been using virtual box for a few years never having this issue arise either.

[dlharper]

There have been a number of posts recently on these forums about similar issues (such as here). VBox versions 4.2 and 4.3 have slightly changed the handling of VT-x in machine profiles. It looks like VirtualBox can't use VT-x for some reason in your context. Formerly that didn't cause a problem but now it gives an error. Try turning it off in the machine settings and seeing what happens.

[RobbieRobski]

dlharper thanks for the suggestion. But I just simply found it easier to uninstall and go back to 4.2. This is just test development stuff and I didn't notice any security related patches in the change logs.

All is well when I went back to 4.2