We are used to closing the cover and letting the MAC go to sleep when we are not using the Mac, but sometimes we find that after closing or opening the cover, the MAC does not go to sleep or open normally. So, how can we solve this problem?
Reset the SMC of MacBook Pro / air. At present, the new MacBook Pro / air (model with non removable battery) can reset the SMC in the following ways:
Turn off the computer.
Connect the MagSafe power adapter (that is, the power cord) to the power supply and MAC (if not already connected).
On the built-in keyboard, press the (left) shift control option key and the power button at the same time.
Release all keys and power button at the same time.
Press the power button to turn on the computer.
Note:When the SMC is reset, the LED on the MagSafe power adapter may change state or turn off temporarily.
P.S. How to make sure that the book after the box cover has entered sleep mode? For MacBook Pro, there is an indicator light under the right palm rest. In sleep mode, the indicator light will emit a soft white light, and there will be no noise in the computer. For MacBook Air, just listen to the noise in the computer, or slightly open the screen to see if it has been turned off.
UPDATE：If the MacBook Pro is equipped with dual hard disks, the boot system from the hard disk installed in the CD-ROM drive may also cause abnormal sleep / wake-up. Therefore, students who are equipped with dual hard disks for MacBook Pro should avoid using the hard disk in the CD-ROM drive as the system disk.
This is the solution to the Mac computer can not normally enter the sleep state and normal open method. Users who encounter this problem might as well try this method, I believe it can solve your problem.