The methods for removing past log entries are different between WinAutomation and ProcessRobot.
In WinAutomation, pressing the "Archive" button in the Logs tab should remove the appropriate logs from the database:
Simply choose the date beyond which the logs will be removed and the path to which they will be archived, and a relevant .dat file will be created.
In ProcessRobot, deleting the entries from the dbo.logs table in the ProcessRobot database is an acceptable solution. Simply execute an appropriate SQL query, making sure not to delete anything of importance. Take great care when executing any query on the ProcessRobot database, as any erroneous query may have unexpected consequences. It is important to mention that this steps is performed at your own risk.