I have a 2011 MacBook Pro. About six months ago it developed a sleep problem - it wakes immediately on sleeping. Occasionally when recently rebooted it will sleep as it ought, but usually not. On each waking, the log says this:
localhost kernel[0]: (AppleACPIPlatform) Wake reason: ?
Not helpful!
I've done all the obvious things (network, bluetooth, USB) and tried to reset PRAM and SMC, though the latter doesn't seem actually to reset.
More info which might be relevant - occasionally when the Mac is powered off and I plug in the charger, it boots.
Last week the original HD failed and I had a SSD installed. I also upgraded the OS from Snow Leopard to Sierra. The fault has persisted through both these changes. This leads me to wonder if this is a hardware issue.
Only other info about the machine is that it suffered the degrading-solder problem common to 2011 MacBooks. Since it happened before the Apple Repair scheme kicked in, I had it resoldered by a third-party.
Thanks for any help!
Edit: Further to this: a few things I've found: a process called 'hidd' is listed as Preventing Sleep in the Activity Monitor. Its parent is called 'launchd (1)'. And
pmset -g assertions
gives the following:
Idle sleep preventers: IODisplayWrangler
And finally - when I put the computer to sleep, it very briefly sleeps (1s or so), but then HD starts up again. The sleep light goes off, and does not wink or re-light, but the display stays off. To 'wake' it again takes 10-15 seconds.