MacBook – How to reset MacBook Air that is booted but shows no screen

I would pay attention to two factors:

1) Do you have an external keyboard attached?

2) The power situation - how/when sleep happens is affected by this

3) If the lid is closed at the time you move the mac.

A couple of examples will help illustrate this:

Recently I found that my external keyboard was not waking up the closed lid mac as I thought it should. I found that this was because the power was unplugged and the 'lid closed' operation only worked with the power actually plugged in.

As another example I found that when my computer was asleep, in order to wake it up - without opening the lid! - the trick was to plug an external keyboard/mouse in and hit a key / move the mouse. This then took the mac out of sleep (though again that may depend on whether you have power plugged in or not).

So here's what happened:

I took the computer to the AppleStore, seeing it was only about three weeks old, and got them to take a look at it. Since it's a company computer I had some company benefits granting me a temporary replacement while they were fixing mine. I took my TimeMachine copy and restored it on to the borrowed Mac. I was surprised to find that the issue still appeared, which was quite annoying. So I restored the Mac again, messed around with the pmsetsettings and tried to reproduce the issue but it was impossible.

I then remembered that the issue started appearing a few days ago when I did a battery calibration (Drained the Mac completely) so I restored to a TimeMachine backup from before that and Boom, the issue was gone. At about the same time they called from the store and said that they couldn't reproduce the issue, so I told them what I had found, came in and got my computer back.

All in all, a really weird story but apparently something related to draining the battery while the computer was still on got corrupted and was then included in the TimeMachine backup.