What causes the exclusion list to be reset or cleared?

The Symantec Antivirus file configuation exclusions list is cleared and I cannot figure out what is causing that to happen.  It's a bit of a PITA to have to check this every week.  Can anyone offer a suggestion as to why this happens and if there is anything that can be done to prevent it or perhaps at least warn me that it happened?

Thank you so much.