I use DFS alot for work, sometimes it just gets grumpy and needs to be kicked in the guts.
Deleting the database isnt easy, becuase widnows keeps a pretty tight grib on anything in SystemVolumeInformation.
Use this script to move the DFS folder and have the service create a fresh new database
Hint – Look for DFS Database events in the application log, not the DFS replication log
REM Removes the broken DFSR configuration database from the system
net stop dfsr
icacls "%DFSR_DB_DRIVE%\System Volume Information" /grant "Domain Admins":F
cd "%DFSR_DB_DRIVE%\System Volume Information"
move DFSR %DFSR_DB_DRIVE%\DFSR_backup
icacls "%DFSR_DB_DRIVE%\System Volume Information" /remove:g "Domain Admins"
net start dfsr
dfsrdiag PollAD /Member:%userdomain%\%computername%
Original Article – http://sheeponline.net/recreate-dfsr-database.html