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this happens to me too and it's very annoying. it won't turn back on if i close it and open it within the next 45 seconds.

Really, though, who likes to wake up 45 seconds after they've gone to sleep?

I've had this issue in the past from time to time as well, but it hasn't been regular. When it does, though, it sucks, so I can understand your frustration. Perhaps if there are a number of background processes occurring, it takes awhile to sleep, and you're opening it before it's "ready" to wake up?
 
i put it to sleep at 19:15

OK.. and you need to wait just a little bit.. like 2 minutes. Try it again.


Open /Applications/Utilities/Terminal.app and type in:

sudo echo "blah"

Type in your admin password when prompted. No, there won't be any indication that it's registering your keypressing, that's normal. Hit return.

Note the time in the log, put it to sleep, let it sleep for 2 minutes, wake it up, and give us everything in the log from something along the lines of:

Jul 20 14:39:49 Hanso sudo: yellow : TTY=ttyp1 ; PWD=/Users/yellow ; USER=root ; COMMAND=/bin/echo blah

To the end.
 
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