Full idle scan not finishing

Hi,

 

I have idle scanning enabled, and it's been fine, until recently.  Now the full time idle scan simply doesn't finish.  I've left the full idle scan run for 10 hours straight, uninterrupted, but when I finally do interrupt it and go into Performance/Norton Tasks, it still says "cancelled".  Then the next time the my computer is idle, it starts all over again.  And then again, and again, etc.  The full idle scan never used to take anywhere near that long, and always completed, and I haven't uploaded anything substantial to my computer.  Does anyone know why this might be?

 

btw, I have Windows 7.  Norton's version is 18.7.0.13  If you need any further info then let me know.

 

Oh and I should point out that the full idle time scan really is running, so it's not like it's constantly being interrupted by something.  The last full go I gave it, it ran for 10 hours straight without completing the full scan.  Likewise, if I run the full scan manually, it completes just fine, in a fraction of the time.