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levmc

macrumors 6502a
Original poster
Jan 18, 2019
687
25
It takes a few seconds to wake up the iMac. This didn't happen when I was using high sierra.
 

ProTruckDriver

macrumors 6502
Jul 28, 2016
282
340
Virginia
I don't have that problem with Catalina. I put the Mac to sleep every night. Morning time I hit the space bar and the Mac is instantly awake.
 

avz

Suspended
Oct 7, 2018
1,721
1,819
Stalingrad, Russia
I am not sure if it is helpful but my MacBookPro7,1 wakes instantly with Mojave, I am using it with my FullHD SONY BRAVIA 43" TV.
 

davidlv

macrumors 68020
Apr 5, 2009
2,291
874
Kyoto, Japan
Which of the three solutions here might solve the problem? https://pdf.wondershare.com/macos-10-14/fix-mac-wont-wake-from-sleep-on-macos-10-14.html
And your 2nd question: Will this problem be gone if I update to Catalina? This depends on the cause of the issue, as yet unknown, so "maybe".
That article is designed to address a related but slightly different issue. Some of the sleep related pmset commands may help: Or use the commands below in terminal or iTerm (I have these set on a 2012 model 13,2 iMac and it wakes up instantly, running Mojave) :cool:
1. pmset -g Use this command in terminal window to show your current sleep settings
hibernatemode = 0 (binary 0000) by default on supported desktops. The system will not back memory up to persistent storage. The system must wake from the contents of memory; the system will lose context on power loss. This is, historically, plain old sleep. This should be Faster than the setting below;
hibernatemode = 25 (binary 0001 1001) is only settable via pmset. The system will store a copy of memory to persistent storage (the disk), and will remove power to memory. The system will restore from disk image. If you want "hibernation" - slower sleeps, slower wakes, and better battery life, you should use this setting.
2. To set hibernate mode to 0 (normal sleep, data kept in ram, nothing written to disk)
sudo pmset -a hibernatemode 0 or
sudo pmset -a hibernatemode 0 standby 0 autopoweroff 0
To delete the now unnecessary sleep file (hibernatemode 0 ) to regain disk space equal to memory,
You can use the Go to folder menu to delete the file, found in the /var/vm/ folder, and named sleepimage. Reboot and simply delete that file,. Or use this:
3. sudo rm /var/vm/sleepimage or sudo rm /private/var/vm/sleepimage
The sleep image file is actually in /private/var/vm/ but /var/vm/ is a symbolic link to that location.
Optional: Create a blanked zero-byte file so the OS cannot rewrite the file:
sudo touch /private/var/vm/sleepimage
Make file immutable:
4. sudo chflags uchg /private/var/vm/sleepimage
If pmset -g shows: autopoweroff 1,
disable this automatic hibernation mode (happens even if hibernation mode is set to 0 on the Mac mini 2012 and iMac)
sudo pmset -a autopoweroffdelay 86400
5. sudo pmset -a autopoweroff 0
when any late model Mac is connected to AC power, it goes into a deeper "safe sleep" mode after 4 hours if there's no activity from wireless/Ethernet/USB devices. It's waking up from safe sleep that's causing issues with Thunderbolt. You can disable safe sleep by bringing up Terminal and entering the two commands shown above:
set the safe sleep timer (standbydelay) to 20 hours, default is 4200 (1.67 hr)
sudo pmset -a standbydelay 72000
6. sudo pmset -a standby 0
Bit 3 of hibernatemode encourages the dynamic pager to page out inactive pages prior to hibernation. So swap can be used even after sleeping (even though hibernatemode is 0, so bit 3 is off). Disable this new, possibly buggy behavior by switching off standby:
 
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levmc

macrumors 6502a
Original poster
Jan 18, 2019
687
25
@davidlv
I didn't read everything yet but do you think it would be easier for me to understand if you make a video instruction of this?
 

davidlv

macrumors 68020
Apr 5, 2009
2,291
874
Kyoto, Japan
@davidlv
I didn't read everything yet but do you think it would be easier for me to understand if you make a video instruction of this?
Sorry, I don't have the time to do that.
Just jump in the water, go to the Application/Utilities/ folder and open Terminal;
Run the commands above (copy paste) one by one.
Check to see if the issue has improved after a reboot.
Report back, it may be that the cause of your delay is related, but maybe due to another issue.
Just a thought, but could you post more system info? What year / model is the iMac, how full is the startup drive? Is that a Fusion drive? Use the "About this Mac" and "System Report" from the Apple menu to find out the info necessary to solve this issue.
Have you tried booting from another HD, run Disk Warrior or other repair software, even Apple's Disk Utility?
The sparse information given in your first post, and your question about whether or not the methods given in that semi-related post would help solve the problem suggest that you are not yet completely comfortable doing this kind of diagnosis.
There are many issues or combinations of small issues that could cause that kind of slow wake from sleep problem.
Do a disk repair run from another startup disk or the Repair partition (reboot while holding down the command + r keys).
Run the commands shown above.
Any improvement? :cool:
 

levmc

macrumors 6502a
Original poster
Jan 18, 2019
687
25
On your number 3 you say "or use this"
Does that mean numbers 3 to 6 is alternative option to numbers 1-2?
I'm using iMac 2017 27inch.
 

davidlv

macrumors 68020
Apr 5, 2009
2,291
874
Kyoto, Japan
On your number 3 you say "or use this"
Does that mean numbers 3 to 6 is alternative option to numbers 1-2?
I'm using iMac 2017 27inch.
That "or use this" is at the end of #2, not in #3, so it means there are two ways to delete the sleepimage file, /private/var/vm/sleepimage.
You can use the finder or the terminal to erase it. That is what that "or use this" means.
Is English your native language? I suspect it is not, in which case you may have trouble understanding this rather technical subject. I suggest you just run those terminal commands, they will not do your system any damage, and they may help solve that "slow to wake up" problem. Report back here after you do that and test for if there is any improvement.
If the sleep related settings are the cause of the slow wake up from sleep, those commands should fix it.
However, there may be other issues too.
 
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