Minor Loss of Fidelity "Location: Defined Names"

[Skulking]

I am using excel 2007, and I am having a problem with saving a file. When I save the file the compatibility checker opens and tells me I have a minor loss of fidelity. The exact message is:

"Some of the formulas in this workbook are linked to other workbooks that are closed. When these formulas are recalculated in earlier versions of Excel without opening the linked workbooks, characters beyond the 255-charachter limit cannot be returned.
Location: Defined Names"

To try and track this down I first went to defined names, I'm not using any and the name manager doesn't show any. I then made a copy of the file, and deleted the tabs one at a time to try and see if that would do it. I have deleted all the tabs in the original file, and created a single new blank tab. I have confirmed that there are no defined names in the names manager, and I am still getting the message telling me there are 22 occurrences of this error.

TL;DR
Error about defined names, but there aren't any in the workbook. Any suggestions what might be causing this and how to fix it?

[newdoverman]

If the other workbooks are not of an earlier version, I would ignore the message.

The times when I get similar messages is when the extension is .xls If all other versions of Excel in use are 2007 or later, convert your files to the .xlsx extension by opening and saving in that format. You may have to re-link where links are used but it could be well worth the time and effort.

I think that this compatibility thing is enough at times to make you go bald pulling out your hair.