File backup failure with "unable to flush I/O writes" Thanks David. The same error did not occur on the following night's backup, so the backup completed successfully. I also changed the option to "use system VSS provider" as you suggested. However, I'm still interested to know if there is a "retry" option when such errors occur. Waiting 24 hours to retry the backup puts files not backed up at risk. At the same time, I don't want to retry the backup during the day when I see the email that the backup has failed.