My Magic Mouse is intermittently losing its connection to my MacBook Pro.

First the mouse becomes unresponsive and a few seconds later, a picture of the mouse appears on the screen wit the words "Connection Lost." Then about 10 seconds later, the connections is "magically" re-established, without any action on my part.

Any ideas on what this could be due to and how I can stop this? I have changed the batteries and they are brand new. My software is also up-to-date unless there is a special bluetooth update that I have to go get somewhere.

  • If you have Xcode 3 it includes a Bluetooth explorer. It will help rule out new interference on bluetooth channels. Adding a wireless phone, microwave oven, or other device that transmits can cause interference.
    – bmike
    Jun 10, 2011 at 16:26

8 Answers 8


Batteries are loose

Apple designed the Magic Mouse battery compartment according to the official specification for AA batteries. Unfortunately, while Apple engineers were quite precise, the manufacturers of batteries are not. In practice, batteries vary in size, just enough to be problematic in the Magic Mouse.

Given that the batteries are hanging inside the mouse with only the tension of the terminal receptacles to keep them in place, incorrectly sized batteries can easily be pulled by gravity, falling down ever so slightly, just enough to lose contact with the electrical pads.

Wiggling the mouse is enough to re-establish contact between battery and the pads. For a while, until they fall again. Thus the annoying disconnect-reconnect-disconnect-reconnect loop.

Piece of thin cardboard

The solution is to use scissors to cut a piece of thin paper cardboard the size of the batteries. Lay this piece over the batteries before engaging the metal cover on the bottom of the mouse. The cardboard should touch only the batteries, but not the surrounding compartment of the mouse. Your goal is to get the metal door to push the paper up against the sides of the batteries, just snug enough to prevent the batteries from falling downward.

I have found the perfect thickness of cardboard to be the box enclosing a 12-pack of soda cans. A business card might do. You need about a millimeter. Thicker than sheets of paper. Card stock might do it, but may not be thick enough.


The battery connection is very sensitive on the magic mouse, which makes the batteries move around slightly when you use the mouse which is enough for it to loose power. Try tapping on it and you'll see.

When this happens, you need to shake the mouse or open the hatch. This usually works.

They should have used the traditional spring to keep the batteries in place.

  • Yes, this is right! The batteries come a bit loose! I solved my problem by putting a folded piece of paper on top of the batteries to keep them from moving down and away from the mouse which causes the connection to be lost. This was to a windows machine, so it's not PC specific, but a mouse issue. The other option is to use batteries that fit tighter - some brands are a bit loose. Jul 31, 2014 at 0:36

I found that just removing the batteries and cleaning the terminals with a paper towel on both the batteries and the mouse fixed the problem. I think the people who used paper spacers on the sides of the batteries and aluminum spacers on the negative end of the batteries actually just cleaned the terminals by removing and installing the batteries and the spacers didn't do anything. May be some coincidence but no loss to try.


How old is the Macbook Pro? Is it still under warranty? Have you replaced the hard drive recently? I presume you've gone through the troubleshooting procedures on Apple's support page.

The first thing I would do is shut everything down, ensure the mouse is turned on first, then restart.

I've done a bit of a search on Apple's forums and I found this. It outlines how someone had a similar problem and did a bit of surgery on the Macbook to fix a loose connection. Not sure if it would be of help.

Of course, the easiest solution, if not the most elegant, would be to purchase a USB bluetooth adapter for $20 or so and see if that solves the issue. If not, it must be an interference or mouse hardware problem.


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Simply fold the post-it and put it between the batteries to solve the problem.


Are the batteries in the mouse old and about to die? That is what happens to my Dad's mighty mouse when the batteries are about to die and need a recharge.

  • read the question. The batteries that he used were brand new.
    – user6124
    Jun 11, 2011 at 0:46
  • Oops. Totally missed that. I'll leave the answer, anyway, just in case someone is searching and that is their problem.
    – Cajunluke
    Jun 11, 2011 at 17:53

It's not that the battery compartment of the Magic Mouse is too big, it's that the positive connection plate is recessed too deeply behind the plastic end cap... and on some brands of batteries (notably Amazon) the tip on the positive end is too short to reach. Putting a small wad of foil in the hole where that tip fits will fix this. If you have the expertise, soldering a small bit of copper on the positive battery tip is an even better fix.

I don't know if you'd call this an Apple error or a battery manufacturer error, but there does seem to be a mismatch.


I had the same problem and tried all the usual apple troubleshooting procedures. Nothing worked for me. Finally, I came across these posts by Michael Kummer and Brad Moon.

Turning off Apple’s Handoff feature worked for me!

From Brad Moon post:

Simply open up your System Preferences, select General, look for a setting called Allow Handoff between this Mac and your iCloud devices and make sure it’s un-checked.

You lose the ability to start writing an e-mail on your iPhone then “hand it off” to automatically continue working on it in Mail on your Mac, but it might be worth sacrificing the feature to finally nail a maddening Bluetooth mouse problem.

(I reported this also to a similar question: Lost bluetooth connection with mouse.)

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