I recently upgraded my mid 2011 Mac mini to macOS High Sierra. I purchased the Magic Mouse 2 about a year ago, but really loathe the charging port on the bottom (unbelievably stupid design, but I digress). As such, I kept my old (original) Magic Mouse handy for when I needed to charge the Magic Mouse 2. I never had problems with this use case in OS X El Capitan.
However, today when I tried to use the old Magic Mouse, macOS absolutely freaked out and neither of the Bluetooth mice could connect. I had to use a generic Logitech USB mouse to "forget" both of them (old and new), then I could reconnect the Magic Mouse 2 after it charged.
So my question:
is the original Magic Mouse unsupported in macOS High Sierra? (edit: it definitely is supported, not the issue). Or perhaps I simply can no longer use the Magic Mouse and Magic Mouse 2 interchangeably?
Update 1: Forgetting and re-pairing both of the the mice was a temporary fix. Nothing else worked, including rebooting.
Update 2: Issue has returned. I again had to fight macOS tooth-and-nail to get the Magic Mouse 2 paired after using the Magic Mouse!
Update 3: One thing I forgot to mention: when the Magic Mouse 2 has lost pairing (after using the Magic Mouse) and I plug it in and switch it on, the "Mouse" section of System Preferences goes absolutely berserk, rapidly alternating between the normal screen and the "looking for bluetooth mouse" screen.