1. It may not be that file as effectively that is the file that has just been scanned rather than the one being scanned.

  2. If you are able to click the Detailed Report button (possibly not) that may tell you what files couldn’t be scanned and crucially why.

EDIT: Files that can’t be scanned are just that, not an indication that they are infected or suspect, just that they can’t be scanned. But there are many legit reasons why a file can’t be scanned, for that we need information on the file name, location and reason why they couldn’t be scanned.