Backup error: Failed to flush the commit table to disk When I try to backup a SQL Server 2008 database, I receive an error:

Backup failed for Server 'SQL2008TEST'.  (Microsoft.SqlServer.SmoExtended)
Failed to flush the commit table to disk in dbid 32 due to error 2601.


Does anybody know the cause of this error?
This usually happens when you have enabled change tracking on the database. A fix was released some time back:

FIX: Backup fails in SQL Server 2008, SQL Server 2008 R2, or SQL Server 2012 if you enable change tracking on the database (Microsoft Support)

As it says there:


  The fix [...] was first released in Cumulative Update 7 for SQL Server 2008 Service Pack 2


The latest (and final) Service Pack 4 for SQL Server 2008 would also contain this fix.