Step 1: Log into your Drupal 7 Admin panel.
Step 2: Once inside the admin area, locate the Reports menu option in the top menu bar and click it.
Step 3: You are now on the Reports List screen. Find and click on the Recent Log Messages option.
Step 4: From here you will see a couple of options for dealing with Error Logs, click on the Clear Log Messages link and the section will expand. You will a gray Clear Log Messages button. Click that to clear the error message log.
Step 5: You will be met with a success message once the error logs have been flushed.