I constantly get this error when using Symantec Veritas Backup Exec, or NTBackup. They both fail. I have moved from DAT72 tapes to external USB hard drives to isolate issue, but issue still occurs. Here is the error from NT Backup:
Error: An inconsistency was encountered in the requested backup file.
Error: C: is not a valid drive, or you do not have access.
Here is the error from Symantec Veritas Backup Exec.
Backup- Shadow?Copy?Components Shadow?Copy?ComponentsV-79-57344-65245 - A failure occurred accessing the object list.
I know they are related and it appears to be a VSS issue. I just cannot get the issue to disappear.