System (PID 4) High Disk usage when opening Outlook and Internet Explorer

When opening Internet Explorer or Outlook, System process or PID 4 begins maxing out HDD usage. When I try cleaning it with Ccleaner, it deletes 12,000 MBs of temporary internet files from IE. I am not sure how to stop this. Is there a service that Outlook and IE use that would do this? Thank you.

What version of Windows?