One of our corporate clients came to us last spring with a MacBook Pro having sleep issues. Specifically, it would go to sleep as soon as it powered on and then not wake up. The machine performed normally for us and passed all diagnostic evaluations. We talked with the client and sent the machine back with the status of “Could not duplicate,” meaning we could not get the symptom to recur.
We did not hear anything further about that machine. A couple of months later, another machine from them with the same symptoms came in. Then, a couple more soon after that. Only in one case did we actually replace anything—one of the machines had a defective battery. We were at a loss to explain why they were having this issue with so many machines. Granted, they do buy a lot of machines, but we had never seen this issue in any machines except for theirs!
Finally, we decided to ship one to Apple to see what they thought, and it returned with a new logic board. After that, every time one of these sleepy machines came in from our client, we sent it off to Apple for a new logic board. This was a workaround and brought a kind of resolution, but still didn’t get to the root of the problem. Then, a couple of weeks ago, one of our consultants, David, was on-site with the client installing some RAM and they started talking about the issue. There were stacks of machines being configured for deployment to employees and the client pointed out an affected one to David.
David picked it up only to discover once again that the machine was fine. After a moment, he placed it back on top of the stack of machines and… it went to sleep and would not wake up. After a little more experimenting, they confirmed that if stacked, the machine on top would not wake from sleep. In retrospect, it was obvious why: the sleep switch is in the body of the laptop and is actuated by a magnet in the display. The magnet is strong enough so that in some cases, the magnet in the machine below would cause the machine on top to sleep. They would send the machines to us and of course, they would work perfectly.
Upon his return to the store, David did some research and found a tech article on Apple’s service provider website that was only a few days old; it described the exact issue he had just seen. David solved a long-standing mystery, the client has modified their procedures, and hopefully, we will not see another instance of this issue!