Magic Mouse stops working under Yosemite

You may have to reset the System Management Controller, to help the peripheral items

be recognized if there is a glitch somewhere in BlueTooth or USB bus, etc. That may be

of help. Also to do a variety of basic things most don't do, to include a restart on occasion

in SafeBoot, run Disk Utility's first aid, to repair disk permissions, then restart normally.

•Intel-based Macs: Resetting the System Management Controller (SMC)

•OS X: What is Safe Boot, Safe Mode?

Depending on the brand of and age of the batteries in the Mouse, they may need replaced.

Sometimes, certain brands of batteries are poorly fitting, and could lose connection, too.

When my old mouse acted up, I introduced it to a potential replacement mouse; set beside

the older one, I told him that this new guy was standing by, and to shape up. It helped...

Good luck & happy computing! 🙂

I followed this procedure and it worked. 🙂

Try to turn wifi off. According to magic mouse doesn't work under yosemite.

Thank you! This solution solved the problem for me--I have been having the same problems as the OP intermittently and sometimes even rebooting is didn't work. But turning off the wifi immediately brought up the "pairing" option for the mouse--and it's a lot quicker than rebooting!

My Mac Mini's power button changed functionality with Mavericks. Now with a fast click of the power button the Mini sleeps. A little longer and you get a shut down dialog, and of course, hard shutdown holding for longer still. I don't know if the MacBook works like that in Yosemite. If it does, use the button to Sleep, then again to wake, and 99% of the time you have a Magic Mouse again, with Mavericks at least. Even if the button doesn't work, you can use control-fn-F2 to give the Apple Menu focus, down arrow to go down to Sleep, and Enter to make it happen. Then wake however you normally do. Still a nuisance, but slightly less intrusive than Restart, particularly if you have something you haven't saved yet. Worth a try maybe.

I only boot Yosemite for short periods from an external drive so far, so I can't vouch that this will work for it. I come from a background where you don't install version zero of anything. I have to say, with a clean install, so far I don't see the problems I read about here. Maybe I need to work for a whole day with Yosemite sometime.

PS. I just tried turning off the mouse in Yosemite (and saw the disconnection reported). Went to Sleep. Turned on the mouse while Sleeping, Woke Up, and the Magic Mouse reconnected just like Startup.

Thanks, that was the solution I was looking for!

I was having a similar problem on an early 2013 MBP-retina: magic mouse couldn't connect, then when I unpaired it disappeared completely, nothing seemed to bring it back. Then I turned off the wifi and ta-da! The mouse showed up and I could re-pair it. Turning wifi back on afterwards caused no problem.

Strange...