Windows 10 VM stopped working

[Weboh]

I have a Windows 10 VM that used to work, but today just stopped working. One of its snapshot VDIs shrunk to 0 bytes and can't be read. It was somehow modified at a date when no snapshot sav files were. I can't open any of the 10 snapshots of it I have, because they all somehow need that one corrupted file. Is there any hope of fixing it? I'm attaching a screenshot of the snapshot folder, the message it gives when the machine fails to start, and the log file.

Code: Select all

Failed to open a session for the virtual machine Windows 10.

Could not open the medium 'C:\Users\John\VirtualBox VMs\Windows 10\Snapshots/{cf4b942a-1b47-42ac-b3eb-1f20ae7e328f}.vdi'.

VDI: error reading pre-header in 'C:\Users\John\VirtualBox VMs\Windows 10\Snapshots/{cf4b942a-1b47-42ac-b3eb-1f20ae7e328f}.vdi' (VERR_EOF).

VD: error VERR_VD_VDI_INVALID_HEADER opening image file 'C:\Users\John\VirtualBox VMs\Windows 10\Snapshots/{cf4b942a-1b47-42ac-b3eb-1f20ae7e328f}.vdi' (VERR_VD_VDI_INVALID_HEADER).

Result Code: E_FAIL (0x80004005)
Component: MediumWrap
Interface: IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}

Snapshot Folder.gif (67.39 KiB) Viewed 829 times

VBox.log

(1.31 KiB) Downloaded 9 times

[scottgus1]

The 12/22/15 seems to be the last snapshot, if I read correctly. You should be able to go back to the previous snapshot on 12/5/2015. Or if you have backed up all the individual vdi's in this snapshot chain, you may be able to restore the missing/damaged file.

That said, that's a lot of snapshots & sav files. Snapshots make a guest more delicate and do not work as backups. They should only be used on guests you're experimenting with and with data you wouldn't mind losing. (The forums are replete with users destroying their important data because they did something wrong with a snapshot.)

If you're using snapshots as a backup routine, copy the guest folder and files instead. A full backup is much more resilient. See this tutorial Moving a VM and re-interpret it as "Backing Up a VM".

[Weboh]

I should be able to go back to any other snapshot, but when I try, I get the same message about that VDI being inaccessible and nothing loads.

I had no idea that snapshots were not supposed to be used like that. I thought that was the whole point of them? Anyway, the data isn't thatimportant--it's just all the released builds of Windows 10 up to this point and I just realized that's it's taking up 100+GB on my 500GiB hard drive... I'll delete them after I get the machine working again.