Recently, I discovered that my 13-inch, Mid 2011 Macbook Air was not waking from sleep as expected when I opened the cover, even if I tapped the spacebar. I needed to press the power key. This was annoying because if the power key is held down too long, the laptop restarts. Ugh.
A web search turned up many instances of people with the same problem but, unfortunately, not many suggestions for how to resolve the issue. I recalled that this problem happened to me once before and then went away. What I couldn't remember was what, if anything, I had obviously done to fix it.
When the problem recurred again a few days ago, I did the web search again. I also considered what I might have changed recently. One page I found gave me an idea. The most recent thing I had changed was to turn on Bluetooth.
Could it be that simple?
I went to the System Preferences and turned Bluetooth OFF. My laptop now wakes as expected.
If you have the same problem but aren't running Bluetooth (or need to use a Bluetooth device), this solution may not help you. In that case, try one of the suggestions given at these pages:
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