Remove Duplicates Not Working — Capital Letters / Uppercase

Why this isn't a bug

Remove Duplicates is working exactly as designed — it's just not designed to be case-sensitive, and there's no setting in its dialog to change that. Excel considers “Apple”, “APPLE”, and “apple” to be the same value for the purposes of finding duplicates, full stop. If your data needs case to matter, the built-in command can't do what you need on its own.

Where this actually bites

It's most damaging with identifiers that were designed to be case-sensitive on purpose — SKUs, project codes, or short codes where lowercase and uppercase versions represent genuinely different things. Remove Duplicates collapses them into one row exactly as if they were the same code, silently losing the distinction.

Making the comparison case-sensitive

The built-in dialog can't do it, so you need a helper column: add a column with =EXACT(A2,A1) compared against a sorted list, then filter or sort on that helper column before deciding what to remove. It's manual and easy to get wrong on a large sheet, since you're now doing the duplicate detection yourself instead of relying on the command.

A faster way to check first

Upload your file below and run a duplicate check that respects case, so you can see exactly which rows would collapse under a case-insensitive comparison versus which are genuinely identical, before choosing what — if anything — to remove.