How to: Rename a SQL Server Agent Error Log (SQL Server Management Studio)
This topic describes how to rename the file where Microsoft SQL Server Agent errors are written.
In Object Explorer, connect to an instance of the SQL Server Database Engine, and then expand that instance.
Expand SQL Server Agent.
Right-click Error Logs and select Configure.
In the Error log file box, enter the new path and file name, or find it using the browse (...) button.
SQL Server Agent will not write to the new log file until the SQL Server Agent service is restarted.