I’ve been using an Apple Magic Mouse for a while and it works quite well for me, until, it doesn’t. Let me explain.
The Magic Mouse connects to one’s Macintosh computer via Bluetooth, a short range wireless protocol. I routinely carry my MacBook Pro to other places in my house leaving my Magic Mouse behind and when I return the Magic Mouse does not automatically connect. Every once in a while it does but it’s rare. I can connect by going to the Bluetooth menu, choosing Richard’s Mouse, and choosing connect but there’s an easier way to connect the now disconnected but running Magic Mouse:
Click the mouse.
I can’t believe I never knew this. No doubt you did but in case you didn’t try it.
Recently my Magic Mouse started tracking badly, very much like an old Apple mouse with a dirty “ball” (yes, old mice had balls, well, one ball). So, I went up to the Bluetooth menu to see what the charge on the Magic Mouse’s batteries were. They showed 100%. Still, I decided to swap the batteries out for a new set and upon putting in the new set the mouse tracked perfectly. This seemed odd to me so I took out the new batteries and replaced the old and the mouse continued to track perfectly.
This discussion at Ask Different led me to the answer: Magic Mouse disconnects randomly.
Specifically, the discussion of batteries in the first answer by Coyote.
It seems that the battery contacts in a Magic Mouse can become corroded over time and simply taking the batteries out, or, more simply, rotating them in place, can clean enough of the corrosion off to make a better contact.
When I put my original (seemingly bad) batteries back in, I had changed their position and made better contact.
This is amazingly simple and no doubt related to my post and thousands of comments on Canon DSLR error 99 problems being caused by corroded body/lens contacts.
While you’re up in the Bluetooth menu you may notice that your mouse is showing a battery level of 100% but the alkaline batteries you have in it are a month old. How is this possible? Another excellent discussion at Ask Different explains: How is the battery level calculated in the magic mouse? and explains why my Magic Mouse was showing 100% charge on its Duracells even as they were a month old.
Bottom line: with alkaline batteries installed in the Magic Mouse, the mouse’s battery level indicator is like a car gas tank that reads full until you have a few miles left.