How to Fix VolSnap Error ..a critical control file could not be opened

If you encounter a VolSnap error like this one:

The shadow copies of volume \\?\Volume{XXXXXXXX} were aborted during detection because a critical control file could not be opened.

You would want to check if a couple of minutes earlier the system ran into Disk warnings and/or other service errors. Those may be causing this as a consequential error.

Alternatively, the error may result from having too many shadows or the host is simply taking too much time to create a VSS shadow.

There are several ways to fix this issue:

• Check the logs for additional clues

• Use VSSUIRUN.EXE to lift all VSS storage area limits (to no limit or unbounded), see screenshots in middle of article: //backupchain.com/Cannot-Find-anymore-diff-area-candidates-for-volume-Volume-shadow-copy-service-error-troubleshooting.html

• The above may be necessary if there isn’t enough VSS area for VSS to work or:

• There may be an excessive number of VSS shadows on the host. If you’re not using any other backup tool it’s safe to delete them all, either using VSSUIRUN.EXE (select and delete each)

or by using the command line

vssadmin delete shadows /all

• Use VSSUIRUN to check if there is a schedule that automatically creates these shadows. It’s common when the Windows feature ‘system restore’ is being used. The ‘next run time’ column in VSSUIRUN next to each drive listed should say ‘disabled’. You should disable all schedules if you find any

• * If the issue has to do with VSS snapshot timing please check if the following key exists in the host’s registry:

HKLM\Software\\Microsoft\\Windows NT\\CurrentVersion\\SPP\\CreateTimeout

The “CreateTimeout” key should be added as a DWORD 32-bit, and it’s value is in milliseconds. On a busy host you may want to shoot for a value of 1200000 => 20 minutes.

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