Anybody else failing to open snapshots once they upgraded their VirtualBox from v5 to v6? Snapshots that were opening just fine are now failing for me with this error ...

HGCM#0: Bad auto mount point size: 0x5

 [ver=3 pass=final] (VERR_SSM_DATA_UNIT_FORMAT_CHANGED).

Result Code: E_FAIL (0x80004005)
Component: ConsoleWrap
Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}

Some very old snapshots are able to open; but most new ones and ALL the ones I save now using VirtualBox 6 are failing to open. Same error above.

My host is Windows10 and the saved VMs are Ubuntu18 guests.

Disclaimer: It should not be an excepted solution as your saved state will be lost.

As I don't have any sensitive data in the saved state. I have discarded the saved state and it works fine for my case.

EDIT: in some cases it looks like if you take a snapshot using the saved state, and then discard the saved state you might be able to recover back to where your saved state was

Steps

1. Right Click on the OS
2. Select Discard Saved State... in the context menu.

Screenshot

Host OS: Windows 10, Guest OS: Ubuntu 18.04, on Virtual Box 6.0.0