Excel app won't accept 2020 dates on one tab, but will on other tabs

EDIT: I think the problem is resolved (see post #3) - thanks, Greg!

PREVIOUS EDIT: I just attached a screenshot of the date-error message I get; probably won't help with debugging, but you can see it supposedly allows 2020 dates, but errors out on them.

Hi all,

Just joined the forum, hoping to get a nudge in the right debugging direction to fix a problem I can't solve on my own. My knowledge of VB and Excel macros is beginner-level at best, but I'm usually pretty good at figuring out existing code for languages I don't know. This time, I'm stumped.

I'm running an early-2000s Excel application to manage multiple stock-trading accounts; the app hasn't been updated in years and the author seems to have gone dark, but the app itself still functions running on Excel 2007 and is essential to my daily trade-management activities.

The problem is that one module will not accept date entries for 2020, but other portions of that same module will accept them, as well as other worksheets in the application. Everything worked fine through the end of 2019 and the problem didn't reveal itself until I tried entering a trading expense for January into the app. It looks to me that some sort of date-validation code has barfed once the current year hit 2020.

I have opened the sheets in Visual Basic developer mode and done searches for date ranges, "2019", "2020", "20" and everything else I could think of, looking for a date-range test and just can't find anything, but I'm sure this is due to lack of knowledge of Excel programming. I would greatly appreciate some guidance into what needs patching to eliminate this bug.


Many, many thanks to anybody who might be able to help me out.

Best Regards,
Jim