I'm having the same issue with a Gemma V.2
I set up this Gemma V.2 about 3 years ago with no problem. I'm now on Windows 10 and Arduino can't seem to find the Gemma V.2 board. I also tried using the Web version of the editor and the Gemma V.2 isn't an option when selecting boards.
Am I missing something? All drivers, libraries, etc. are installed as far as I can tell. Does the Gemma V.2 show up under a different name on the Web editor?
I didn't start a new thread since this one was relatively recent as far as issues go. Thanks in advance if anyone responds.