The user who posted this question is hitting a wall that every spreadsheet power user eventually faces: the moment when exact-match logic stops being enough. Their formula is clean, their intent is clear, and they are one wildcard away from a breakthrough. Our take is straightforward: they are thinking about this exactly right, and the solution is simpler than they fear.
The core issue is that `COUNTIFS` treats each criteria range as a binary gate, either the cell matches exactly, or it doesn't. That works fine when your data is pristine and predictable, but the real world is messy. In this case, column C contains concatenated values like "A; B; C", and the user wants to detect whether any part of that string appears in another row's C column. That is not a flaw in their logic; it is a limitation of the tool they are using. The good news is that `COUNTIFS` does support wildcards, but only if the criteria is a text string that you control. The user cannot simply drop an asterisk into the range reference. What they can do is wrap the criteria value with asterisks: `"*"&C2&"*"`. That tells the function to treat C2 as a fragment and match any cell that contains it anywhere. Applied to their formula, it becomes `COUNTIFS($A$2:$A$10,A2,$B$2:$B$10,B2,$C$2:$C$10,"*"&C2&"*")`. That single change transforms the formula from a rigid exact-match checker into a flexible conflict detector that catches partial overlaps.
But here is the practical consideration that matters more than syntax. Wildcards introduce ambiguity. A partial match on "B" will also match "AB", "BC", and even "B;" by itself. If the data in column C is always a semicolon-delimited list, that is probably fine. If it contains single letters that could be substrings of longer entries, false positives will creep in. The user should test with representative data before trusting the output blindly. A quick sanity check: if "B" appears as a standalone entry in one row and as part of "AB" in another, does that truly represent a conflict in their workflow? Only they can answer that. The formula will do exactly what it is told.
This is the kind of problem that makes spreadsheets feel brittle, until you learn to work with their quirks. The user has already done the hard part: they identified the gap, articulated the desired behavior, and asked the right question. The wildcard trick is a small fix, but it unlocks a much more realistic view of their data. We hope they test it, tweak it, and then apply the same principle to other columns where partial matching makes sense. Because the goal is not to make formulas complicated for the sake of it. The goal is to make them smart enough to handle the data you actually have, not the data you wish you had.