My colleague's iMac connects to my MacBook Pro via Bluetooth without my consent & messes things up!

So, I'd be using my Magic TrackPad or listening to music via Bluetooth headphones and suddenly the mouse cursor would start jumping around or the Bluetooth audio would start breaking up, and that's when I know that my colleagues iMac has connected to my computer. I go to the Bluetooth menu and I disconnect it. After a little bit or awhile, it connects again...

No one knows how or why this happens.

Could someone please tell me what's going on and how to stop it?

Oh, I forgot to mention, another one of our colleagues also complains about this particular iMac connecting to his MacBook Pro.

Update: immediately after posting this, it happened and I took a screenshot. Here it is

Mahmoud's 27 iMac is the culprit.

Another update: Mahmoud's 27 iMac does not appear in the list of paired devices

Solution 1:

I had the exact same issue and the culprit was an app I had installed called MacID, version 1.1. I deleted MacID and the problem went away but supposedly you can upgrade it and fix the issue as well

Reference: https://discussions.apple.com/thread/6702053?tstart=0

Solution 2:

What happens when you select Mahmoud's 27 iMac in the Bluetooth menu? Does it show Connect to or Disconnect from Network, or something else?

I would bet Mahmoud's iMac is set up to share its internet connection over Bluetooth, which would probably also explain why it's not showing up in the Bluetooth devices list. Try looking under Network in System Preferences and see if Bluetooth PAN appears there. If so, click on it, and I think it will show Mahmoud's 27 iMac in the Devices list.

To disable this, on Mahmoud's iMac go to System Preferences > Sharing, click on Internet Sharing on the left-hand side, then either uncheck it (to disable sharing completely), or next to "To computers using:", uncheck the box next to Bluetooth PAN. If Mahmoud doesn't want to disable this, on YOUR computer you can go to System Preferences > Network, click on Bluetooth PAN on the left and click the minus sign at the bottom of the list.

Solution 3:

When the Bluetooth device is connected, press ALT/OPTION and click the Bluetooth icon. When you select the device in the list you will see a Remove option that should stop if from connecting in future.