When backing up SQL using Windows Authentication you may have problems backing up SQL
in the event logs you may see an error like this
"W [!!] Query failed: The server principal "NT AUTHORITY\SYSTEM" is not able to access the database "R32_Live" under the current security context. "
In order to resolve this give the NTAUTHORITY\SYSTEM account permissions from SQL server manager and this will resolve the problem, an alternative solution is to have the GBM login using the database login method (SA)