After upgrading to R9, you are seeing this message in the System Log
"Database backup failed ([Microsoft][ODBC SQL Server Driver]Query timeout expired)"
This is a known issue and is being investigated.
SOLUTION / WORKAROUND
We advise that you use SQL Management Studio to perform a backup of the ksubscribers database.
The steps to do this can be found here - http://www.serverintellect.com/support/sqlserver/database-backup-ssmse/
You can also use an SQL Maintenance Plan to schedule the backup through SQL, steps to do this can be found here - https://msdn.microsoft.com/en-us/library/ms191002.aspx