Differential SQL backup will only run Full backup

[schraids]

I just recently upgraded to the Agent for Applications and Databases, and have been doing some testing on SQL backups.  I scheduled a full backup of each database on all servers with SQL installed, which completed without issue for the mostpart after some tweaking.  My problem is, that on a couple servers, each time a differential backup is run, BE completes a Full backup.  Checking the job logs for the server, I see the message 

Running a full backup of database 'xxxxxxxxx' on SQL Server 'xxxxxxxxxxxx\MSSQLSERVER' because either a full backup does not exist or the last full backup was not run by Backup Exec.
 

I have tried expiring all jobs, running a full, then a differential immediately after the full completes, and another differential after that.  I get the same results each time, so i am basically only able to run Full backups.  Other servers are doing the differential backups as expected, with no issues.  Any ideas on a fix to this issue would be greatly appreciated.

[lmosla · Accepted solution]

Hi,

Make sure that there isnt another type of backup application or utilites running. These would conflict with the full and cause Backup Exec to not see it as a full backup.  

If there is any antivirus scan running make an exclution for the Backup Exec processes and the database files.

Try recreating the job 

check out this link: 
Best practices for Backup Exec 2014 Agent for Microsoft SQL Server

[schraids]

If SQL is backing up via a maintennace plan, will this cause Backup Exec to do a full backup each time?

[pkh · Accepted solution]

Normally this will give you another error message.  Try stopping the SQL maintenance and try to do the backup again.

[schraids]

It looks like it was the maintenance plan that was causing BE to do full SQL backups each time.  Plans are disabled now, and incrementals are working properly.  Thanks for the advice!