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Big Sur wake/sleep problem

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imac 27 inch 2019


just did the update to the big sur and now whenever the computer goes to sleep it will not wake 


Sleep Wake failure in EFI


I have been reading some comments and realize this is a problem, can someone give me a hand fixing this?

I reinstalled the operating system 

I did the SMC and reset the NVRAM with directions from applecare I'm beginning to think they don't know much about their own computers or atleast the guy I got! 



Edited by rotorsport

Hmm. Since you say that you have spoken to AppleCare, I will assume that you’re using an Apple iMac rather than a hackintosh?...


The first line of the problem report says “Sleep wake failure in EFI” which perhaps gives us a area to consider. If you are using a “real” iMac, then the EFI partition should just contain Apple code. Can you confirm that you are not using a third party boot loader (e.g. Clover or OpenCore)?


If you are “pure Apple”, then did you encounter any problems during the update process? If Apple ships an EFI update alongside the OS, then the install process typically reboots at least twice (sometimes more). 

Sleep/wake can be affected by peripherals. Try disconnecting the USB devices (Dymo, printer, etc...). Also check with the makers of your peripherals to see if they have any software updates. The transition from kernel extensions KEXTs to DriverKit extensions DEXTs moves a step forward with Big Sur. It’s worth checking. 

You can also try “safe mode” it disables non-Apple extensions. This may help prove the issue is related to a peripheral or some other piece of non-Apple software.

yes I'm using a 2019 Imac I'm guessing I'm on the wrong site?


no third party 

no problem with the install

I have disconnected all peripherals


I do have parallels loaded with windows 10   




it is still giving an error 

Screen Shot 2020-12-31 at 5.45.56 PM.png

This Reddit post discusses similar symptoms. Mainly for MacBooks although it may still be relevant to the iMac.


Some say that a second SMC reset worked for them. Some say they get the symptoms after swapping to a third party SSD, in these cases using the Terminal command line pmset command to disable hibernate helped. Some say it was a fault and AppleCare exchanged their platform




so Disconnected all the peripheral devices, and update all the drivers  and reset the SMC and NVRAM so far it looks like I might have success. 


it has run this afternoon and gone to sleep and woke as it should, so here is to fingers crossed.




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