I’m on a Mac OS X 10.14.6 running Illustrator 23.0.4. It may turn out I’ve got some kind of conflict and it really works for everyone else. I'm also planning on submitting a Bug Report if there are no working solutions. It will speed things up immensely, but even if I’m finished this project by the time you reply, leave an answer-Please! I’m very curious to know what the issue is. So… Does anyone have any idea how to get the Pathfinder Panel > Merge keyboard shortcut to work?! The command is definitely executing-I checked a few things to be sure: “Undo Merge” appears in the Edit Menu, and “Merge Again” in the Effect menu, among other things. Unfortunately, using it doesn’t actually Merge the two half-circles into one whole circle.

I checked, but there wasn’t an existing command key for it in my keyboard shortcuts. Going back and forth to the panel like that, with 100 circles-even when I move the panel directly below the row of circles I'm working on-is quite tedious and time-intensive. Pathfinder Panel > Pathfinders: Merge works perfectly if I click on it in the panel-that’s not the issue. I’m merging about one hundred (100) fill-only half circles into whole circles-fill only.

Illustrator pathfinder panel