XML Error in TFS Power Tools Backup Plan

Whilst checking the Windows Event Log on my server I found this worrying error being reported by the Team Foundation Server Power Tools Backup & Restore Tool :

Error: Tfpt Backup Restore : There is an error in XML document (499, 100).

I posted an article about using this tool to backup your TFS server in September, and it has been successfully backing up daily since that time. The above error has been reported after every daily backup for the past few weeks it seems. It immediately follows an information event from MSSQL$SQLEXPRESS stating that the “Database has been backed up”. To investigate more I opened the TFS Admin Console on the server and clicked “Take Full Backup Now” whereby I got the same error interactively – well at least it’s consistent.

From here you can open the log, and in that I can see it’s reporting that the BackupSets.xml file in the root of the backup target location is invalid:

_[Info   @20:30:15.977] Backup Set Name Tfs_DefaultCollection database Backup
[Info   @20:30:15.977] Backup Set Description Tfs_DefaultCollection database - Full Backup
[Info   @20:30:15.977] Adding database Tfs_DefaultCollection to the backupset
[Error  @20:30:16.352] System.InvalidOperationException: There is an error in XML document (499, 100). —> System.Xml.XmlException: There is an unclosed literal string. Line 499, position 100.
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On opening the file there appears to be nothing wrong with the XML as such but in my case it didn’t seem complete, as the last successful backup only detailed one entry not the usual two (*.bak and *.trn files). This file seems to be record of the backups as opposed to being core to the actual SQL backup process so I deleted/renamed the BackupSets.xml file and ran another full backup. This time it worked fine and a new BackupSets.xml file was created. It’s now running fine again.