Failed to load unit HGCM (VERR_SSM_UNEXPECTED_DATA)

[ivoef]

I have encounterred the error Failed to load unit 'HGCM' (VERR_SSM_UNEXPECTED_DATA) after upgrading VB from 4.1.2 to 4.1.8. I am not able to restore any of my snapshots for WinXP hosts (stored under 4.1.2 version). The Win7 snapshots (stored under older version) are restored without any problem.

There is an error message:
Failed to open a session for the virtual machine Windows XP.

Failed to load unit 'HGCM' (VERR_SSM_UNEXPECTED_DATA).

Result Code: E_FAIL (0x80004005)
Component: Console
Interface: IConsole {1968b7d3-e3bf-4ceb-99e0-cb7c913317bb}

Thank you for any help.

[ivoef]

Today I have found a workaround for the error. First I have tried to follow instructions described in "Acceleration not working after upgrade to 4.1.8" thread. Unfortunatelly this didn't work for me. Nevertheless the solution is not so complicated.

1) Open Virtual box manager GUI
2) Restore the snapshot for which the error "Failed to load..." occurs
3) Discard the snapshot (the yellow arrow in main top toolbar) - do not DELETE the snapshot!
4) The discarding snapshot is like turning off the machine without proper OS ending. But this doesn't hurt me.
5) Start VB guest. The restored snapshot will reboot without any problems.
6) Save rebooted snapshot. Now restore newly saved snapshot. Everything shoudl be OK.
7) Delete old (not working snapshot)
8) Repeat for every failing snapshot.

Good luck