I'm getting this error in Source Control Explorer
I checked the TFS Server 12.0.31101.0 (Tfs2013.Update4) with SQL Server 2014 12.0.2000.8 (X64)
and it appears the windows event error log is
A user request from the session with SPID 52 generated a fatal exception. SQL Server is terminating this session. Contact Product Support Services with the dump produced in the log directory.
A fatal error occurred during a full-text population and caused the population to be cancelled. Population type is: AUTO; database name is Tfs_DevCollection (id: 10); catalog name is TeamFoundationServer10FullTextCatalog (id: 5); table name WorkItemLongTexts (id: 966294502). Fix the errors that are logged in the full-text crawl log. Then, resume the population. The basic Transact-SQL syntax for this is: ALTER FULLTEXT INDEX ON table_name RESUME POPULATION.