When you have repeating calendar events in your CMSMS and you update them you will need to clean out your MySQL database to clear out those old event entries. Here is how to 0ptimize MySQL database tables in phpMyAdmin:
• Log in to your MySQL database
• Click the database table to be optimized on the left side of the screen
• Click the Operations tab
• Under Table maintenance, click Optimize table
NOTE: The Optimize option may not appear for every table. If it does not, that generally means the table is already at maximum optimization.