Using DiskShadow to Determine Issues with VSS.

Problem

Veritas System Recovery (VSR) backups failing due to VSS writer errors.

Error Message

E4F3000F: Unexpected VSS writer error. Check the application event log for writer specific error.

Solution

Using the Microsoft DiskShadow utility ( https://technet.microsoft.com/en-us/library/cc772172.aspx), we can check the stability of the VSS writers independently from VSR.

Example test using DiskShadow:

1. Run command prompt as administrator
2. Type diskshadow and press enter (to enable logging to a file, use the /l switch. Example command: diskshadow /l c:\diskshadowlog.txt)
3. Type set verbose on and press enter
4. Type set context volatile and press enter
5. Type add volume c: and press enter
6. Type begin backup and press enter
7. Type create and press enter

After entering the 'create' command, the shadow should now be created. If the process fails, detailed information should be logged regarding the cause of the failure.
For step #5, add each volume that you are backing up using VSR. If your VSR backup includes volumes C/D/E, ensure all 3 volumes are included when running DiskShadow. This ensures the test with DiskShadow is equal to your VSR backup (enables you to compare the results between VSR and DiskShadow).

8. When the test is complete, type end backup and press enter
9. Type exit and press enter

If any writers fail during this test, you must troubleshoot the issue (via Microsoft Support if necessary) to ensure that all VSS writers are functioning correctly before using VSR to backup the same volumes.

Note 1: Always use the VSSADMIN LIST WRITERS command to check the state of the VSS writers.

Note 2: If any VSS writer is not stable at the time of backup (stable means that State = 'Stable' and Last error = 'No error'), the backup job will fail. Below shows an example of a stable VSS writer using the above VSSADMIN command: