virtualbox.org

Yesterday I made a VM for CentOS and attempted to start it and it all looks fine but will completely lock up around 30 to 60 seconds or so after starting the VM or if I try to interact with the VM in any way it will lock up immediately. And the only way to terminate the program is to kill it in Task Manager.

I tried running some other VMs I have that host Windows 10 and XP and which worked fine the last time I ran VirtualBox but they are now doing the same thing.

I'm running VirtualBox 6.0.10 r132072 on a Windows 10 Pro 1903 that is fully up-to-date. I have not installed any programs since the last time I ran VirtualBox and it was working correctly. I've reinstalled VirtualBox but that didn't seem to make a difference.

I've attached the log file from the CentOS VM and can attach some from the other VMs as well if needed.

Thank you for your help!

Oh, and I forgot to mention that sometimes when shutting down or restarting Windows I'll get a VirtualBox memory error. I'll try to make a note of it the next time it happens if that would help.

Your log shows the usual Windows 10 problem:

00:00:02.019720 HM: HMR3Init: Attempting fall back to NEM: VT-x is not available
00:00:02.067400 NEM: WHvCapabilityCodeHypervisorPresent is TRUE, so this might work...

See I have a 64bit host, but can't install 64bit guests Carefully go through each command in the 2nd & 3rd posts. Based on my perusal of successful fixes for this problem, the silver bullet appears to be the "bcdedit" command & complete power-down in post 2 point 1.

You also have some wiggle room on the number of processors you can give the guest:

00:00:02.019314 NumCPUs <integer> = 0x0000000000000001 (1)
.....
00:00:02.593131 CPUM: Physical host cores: 4

If you don't plan to run a lot of guests at once you could give this guest 2.

scottgus1 wrote:Based on my perusal of successful fixes for this problem, the silver bullet appears to be the "bcdedit" command & complete power-down in post 2 point 1.

Yep, that was it. Even though I already had all the Hyper-V stuff disabled running the "bcedit" command fixed the problem. Thank you so much!

scottgus1 wrote:You also have some wiggle room on the number of processors you can give the guest:

00:00:02.019314 NumCPUs <integer> = 0x0000000000000001 (1)
.....
00:00:02.593131 CPUM: Physical host cores: 4

If you don't plan to run a lot of guests at once you could give this guest 2.

I currently have to run 3 VMs simultaneously so that's why I have it set to 1 CPU. But if I ever do run it on its own I'll definitely change that. Thanks for the tip.

Glad you're up and running!
If your guest is working fine on one processor now, do like I do: follow the "If it ain't broke don't fix it" paradigm.

So I figured out it was the Windows Sandbox feature that came with the Windows 10 1903 update. The update must have enabled the Hyper-V features so that the new Sandbox feature would work but for some reason, the Hyper-V features did not show as being enabled (I'd specifically disabled them a while ago due to some other problems they were causing) so I didn't put 2-and-2 together.

There's probably the official "Hyper-V" setting that would allow you to run virtual machines, and the "Sandbox" feature that uses the same substructure that "Hyper-V" uses, and they both turn on the substructure, which hogs VT-x. The 3rd post in the "64-bit guests" tutorial has a list, and the list just keeps getting longer....