virtualbox.org

Hi,

I have a Windows 10 Virtualmachine.

After (I think) certain Windows 10 updates de virtual machine stop booting; it stays stuck and it won't open at all.

I really don't know why is this happening.

I hope you can help me.

Sincerely,

Try setting the VM to 2 processors if it is not already.

If that doesn't work, right-click the guest in the main Virtualbox window's guest list, choose Show Log.

Search the far left tab's log for this text:

Attempting fall back to NEM

If you find it, Hyper-V is enabled. You have two options:

1. Try the 6.1.35 test build. Save the test build installer until you update again later. You'll need it if your host's MSI installation database goes south (they do) and the installer will not be available for download after the next even-number version gets released.

2. Turn off Hyper-V. See HMR3Init: Attempting fall back to NEM (Hyper-V is active).

If you don't find that text, save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.

Hi,

It was difficult to disable something so easy.

I had to run the cmd and follow the steps on the article you suggested.

The key was to disable the Windows Defender's Core Isolation.

I does not make sense because I have always had this feature on, probably the updates of the software had something to do with this.

Why do you think?.

Thanks for the information it was quite useful and solved the problem.

Windows does update things that turn on Hyper-V; we see such reports all the time.

Glad you're up and running!