StuffIt Expander gets a bit confused.
Mac OS X includes a copy of StuffIt Expander, an archive decompression utility, and it has a handy feature whereby if it can’t decode a file, but knows of other applications on the system which also register to handle the relevant file-type, it’ll offer to hand-off the file to the other application in the hope that you’ll still be able to decompress it. Very nice.
However, it sometimes gets a bit confused, as shown in the screenshot below. Putting aside the typo in the dialog text (“might to be able to”), the other application it’s referring to here is… itself. Not another installed copy of Expander; literally the same application. Time to add a quick if-statement, methinks.
And yes, if you click “Try”, it will cheerfully ask you the same question again, and again, and again. I guess you’ve got to admire its tenacity.