Assume that you have enabled the Change Tracking feature for a database in Microsoft SQL Server 2014. When you perform backup or checkpoint operations on the database, the operations fail with error 2601. Additionally, error messages that resemble the following are logged in the SQL Server error log.
Cannot insert duplicate key row in object 'sys.syscommittab' with unique index 'si_xdes_id'. The duplicate key value is (KeyValue).
Error: 3999, Severity: 17, State: 1.
Failed to flush the commit table to disk in dbid DatabaseID due to error 2601. Check the errorlog for more information.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.