Can't use Open File Backup for Drive C, Error -1017 Insufficient Permissions
Check the Windows Event Log on the source computer for VSS or Shadow Copy Service errors. You can then use the Windows Event ID (and a Google search) to identify the cause of the VSS Failure and consult with Microsoft for a solution. No settings can be changed in Retrospect to fix this error since the problem is being reported by Shadow Copy Service itself. Once you correct the problem with the Shadow Copy Service, the error will go away.
VSS could be failing due to a conflict with a 3rd party program that is already utilizing the Volume Shadow Copy Service. The errors in the Windows event log will help identify the problem.
The error -1017 for Open File Backup will not stop the backup from completing, but you may see some -1020 Sharing Violation errors for files that are open and can not be copied. If you can fix the -1017 error, the -1020 errors will go away.
Last Update: 11 de octubre de 2012