Resolve the corruption issue on the Windows side, or create a new user account with the same permissions as the existing "agent credential" user, and enter the details on the Agent > Set Credential page.
5) go to Schedule Volumes page and ensure that at least one of the listed disks or partitions
6) you may notice that the backups on the machine are completing successfully when ran at a particular time. Changing this schedule of the backup causes it to fail with this error. Sample screenshot below from the 'Backup > Backup Logs' page.
Looking at the times, immediately this tells you that quite possibly something else is running at this time that is causing the backups to fail. So from here check the following:
a) Check the agent logs (on the 'Agent > Agent Logs' page) for any connectivity issues at the time of the failure.
b) Check the procedure logs for any running procedures that might be impacting the backup schedule, such as:
- Disk Defrag (kills backups)
- AV Scan
- AV Updates
- Patch Updates
NOTE: Patch and AV updates can run for some time, so even if they are scheduled to run some hours prior to the backup schedule, they can still interrupt the backup causing it to fail.
c) Check the event logs on the machine for any other processes that may be running. The event logs may also provide some valued information surrounding the failure, such as the credential user running the backup may not have permission. (The user must be part of the local administrators group and backup operators group to run backups).