If you want to identify which tasks don’t start at 8 a.m. and don’t finish at 5 p.m., here’s how:

Enter the following formula to a custom flag field, for example, Flag1, and then filter for tasks whose Flag1 field doesn’t display Yes:

Format( [Start], “hh:nn AMPM” ) & ” ” & Format( [Finish], “hh:nn AMPM” )
Like “08:00 AM 05:00 PM”

The filter will also work for manually-scheduled tasks whose Start and Finish fields contain valid dates.