A few weeks ago, my wife lost her iPhone 4 and we bought another one. When I set up the phone in iTunes, I did a restore of the backup of her old phone and everything worked great. Except that I could not get her phone to show up in Find my iPhone. I tried numerous times to delete and add the MobileMe account and I could not get the phone to show up. Not in me.com; not in the Find my iPhone app on my iPhone; not even in the Find my iPhone app on her own phone!

There was another weird symptom. When I tried to switch off Find my iPhone it instantly switched back on. This is kind of hard to explain, so here’s a video that shows the problem.

Deleting the MobileMe account and adding it back did not fix it. FMiP still switched itself back on.
Restoring to a previous backup did not fix it.
Restoring as new worked but it nuked all of my wife’s data, so I would then have to do a lot of manual restoring.

My fix:

1. Restore iPhone to latest backup with all of the data. All data now there, but FMiP switches itself back on again. (Tried deleting and recreating MobileMe account. No dice.)
2. Go to me.com and remove the iPhone.
3. On the iPhone, delete the MobileMe account
4. Add the MobileMe account back again, but set Find my iPhone to off initially.
5. Go back into the MobileMe account and turn FMiP on. Answer yes to two prompts – one that syncing will be disabled and one that location will be tracked.
6. Refresh me.com, iPhone shows up! On the iPhone, I can now turn FMiP on and off at will!

Yay!