Virtual machine files not accessible after upgrade to Win11

The problem described in the forum post is not that the files are gone, but that VirtualBox no longer knows about the existing virtual machines after the Windows 11 upgrade and reinstall.

When Windows 11 removed VirtualBox during the upgrade, it did not delete the VM data (the folders with .vbox and .vdi files). But after reinstalling VirtualBox, the program starts with an empty machine list, so it doesn’t automatically reopen your old VMs even though the files are still on disk.

This usually happens because:

VirtualBox’s machine registry was reset​

VirtualBox keeps a list of registered VMs in:

Code:

C:\Users\<your user>\.VirtualBox\VirtualBox.xml

When the program was uninstalled, this registration was removed.

Solution: Re-add ("register") the existing VMs manually​

You can recover everything by:

1. Open VirtualBox
2. Click Machine → Add…
3. Browse to each VM’s folder and select the .vbox file
   (e.g., C:\Users\<you>\VirtualBox VMs\<VM name>\<VM name>.vbox)
4. The VM will reappear exactly as before.

If you only see .vdi files​

If the .vbox file is missing or corrupted, you can create a new VM and attach the existing virtual disk:

1. Create a new VM with the same OS type.
2. When asked for a disk, choose Use an existing virtual hard disk file.
3. Select the old .vdi.

Also ensure you installed a current VirtualBox version​

Windows 11 requires VirtualBox 6.1.28 or newer. If an older version was installed, it may refuse to open VMs.

Click to expand...