Macworld alumni Dan Moren was trying to get Air Drop to work between his iPhone and his MacBook Pro a few days ago. We’ll let him explain what happened next:
I turned to the troubleshooter’s best friend, Google, and typed in my mystical incantation to see what the all-powerful Internet hive mind suggested. Here are the suggestions I found, all of which I tried:
* Turning the iPhone’s Wi-Fi off and on again.
* Turning the iPhone’s Bluetooth off and on again.
* Turning both the iPhone’s Wi-Fi and Bluetooth off and on again.
* Turning AirDrop Off and on again.
* Turning the iPhone off and on again.
* Hard restarting the iPhone (holding down the Home button and Sleep/Wake button).
* Resetting the Network Settings.
* Logging out of my iCloud account and back in again.
But none of these worked… Until he hit upon what might be a solution, albeit strange and even unlikely:
I realized I hadn’t tried to force-quit and restart the Photos app, so I did that. And weirdly enough, that seemed to make AirDrop work again—at least for now. Yet I still can’t be entirely sure that that’s what actually fixed it
Force Quitting an app is more than just quitting it, and there’s a variety of ways of doing so. The easiest is to open the Force Quit dialog box by holding down Option (Alt) + Cmd, and tapping the Esc key. Then select the app in the list and tap the Force Quit button.
Alternatively, you can use Activity Monitor, which you’ll find in the Utilities folder of the Applications list. Use the search field of the app to search for Photos, and then select the app in the list of results. Then click the circular X button at the top left, and click Force Quit in the dialog box that turns up.
Note that searching in this way will turn up Photos helper processes. Dan didn’t mention if he quit these too, but if you STILL can’t get Air Drop to work then it’s worth a try Force Quitting those too using Activity Monitor.