Quick scans

I have my antivirus set to run a quick scan after every anti virus definition update. I have noticed over the past several days (8/28/09 and recent)

That there are no quick scans done, or if they are, it is like 1 second with no files scanned. I have usually had at least 1 quick scan a day that went through 5,000+ files. But recently not. Any feedback?