My problem is there are at least 50 - 75 records that are not being counted in one of my calculations. My calculation is to count each RecordID number (all unique and auto-entered) but for some reason, FMP overlooks these specific records. This calculation works for all of my other inventory items. Did I enter them incorrectly?

You've said it counts each record ID number, but you haven't shown us HOW. Is there a relationship here? A summary field? What specifically is the calc/summary? If there's a relationship, what is it?

The calc is: Count(RecordID) - Count(Location), with Location as a calc field: Location = "Used". The result is placed in another table labeled Totals. The relationship I have between these two is through a unique, text field ProductID.

I hope this helps.

I also found that when I make a report to count how many items are not "Used," FMP lists the items (whose records are overlooked) twice with two different quantities. The total of the two different quantities is what the calculation should total. The calculation is only taking the first value, and not counting the second.

I've decided just to redo those records. Thanks for your help Ender!