Reregister VSS components to resolve NetWorker backup failures
Sometimes re-registering VSS core components can fix errors and allow NetWorker backups to continue successfully.
On the failing client, use the following commands to attempt to resolve VSS related errors:
cd /d %windir%\system32 net stop vss net stop swprv regsvr32 /s ole32.dll regsvr32 /s oleaut32.dll regsvr32 /s vss_ps.dll vssvc /register regsvr32 /s /i swprv.dll regsvr32 /s /i eventcls.dll regsvr32 /s es.dll regsvr32 /s stdprov.dll regsvr32 /s vssui.dll regsvr32 /s msxml.dll regsvr32 /s msxml3.dll regsvr32 /s msxml4.dll vssvc /register net start swprv net start vss vssadmin list writers
Check the vssadmin output that all your writers are displayed without errors. If errors are still shown, then a reboot of the server will be required.
After the reboot, open a command prompt and rerun the vssadmin command
If the output was clean, then attempt another backup of the failed client;