Hey there, Steve,
Thanks for visiting the Apple Support Communities. From your post, I understand that you're having some trouble with your iMac computer's sleep/wake behavior. Specifically, when you've turned Do Not Disturb on and put the computer to sleep with hot corners, the computer will wake unexpectedly when receiving a notification. I'm happy to help!
There are certain situation in which the Mac may wake up when receiving notifications, or in other circ*mstances. The information below from If your Mac doesn't sleep or wake when expected - Apple Support details those scenarios, and also links to more information about each:
If your Mac wakes unexpectedly
Your Mac might wake for these activities:
- Network activity that uses the Wake on Demand feature. Examples of network activity include iTunes sharing, photo sharing, printer sharing, file sharing, and using Back to My Mac.
- Enhanced notifications from FaceTime, Messages, and other apps and services.
- Bluetooth activity. To prevent Bluetooth devices from waking your Mac, choose Apple menu > System Preferences, then click Bluetooth. Click the Advanced Button, then deselect "Allow Bluetooth devices to wake this computer."
If you have a MacBook Pro (2016 or later) or MacBook (Retina, 12-inch, 2017), note that these models are designed to start up when you open their lids or connect them to power.
Since you have Do Not Disturbed enabled, all notifications should be stopped regardless of what type, though. However, Do Not Disturb will automatically turn itself off at midnight local time. So, if you turn it on at 10PM and go to bed, at midnight (two hours later), Do Not Disturb will turn itself off and your computer will begin to behave as described in the information above. You can specify a time frame for Do Not Disturb, though, which disregards the automatic time frame in System Preferences > Notifications. If you were to set this for 10PM-7AM, for example, Do Not Disturb will not disable at midnight. You can get more information here: macOS Sierra: Receive or stop notifications .
If you've set a time frame for Do Not Disturb and the computer is still waking unexpectedly, try the following steps (also from If your Mac doesn't sleep or wake when expected - Apple Support ):
If the previous steps don't work
These additional steps may help identify or resolve the issue:
- Reset the SMC.
- Reset NVRAM.
- Disconnect external devices other than your Apple keyboard, mouse, and display. If that resolves the issue, gradually reconnect your devices, testing each time, until you find the device that is interfering with sleep. Then check the documentation that came with the device, or contact the device manufacturer.
- Start up in Safe Mode to see if the issue is related to non-Apple startup items, login items, or kernel extensions.
- Try to isolate the issue by using another user account.
If you still see the issue, contact Apple Support.
Cheers!
FAQs
If your Mac wakes when you're not present, something may be pressing the trackpad or mouse button, or keyboard keys. Apps: Apps that access a disk can keep your Mac from going to sleep. For example, Music accesses your disk to read the songs it plays, and DVD Player accesses the optical disc drive to play movies.
How do I fix night mode on my Mac? ›
Use a light or dark appearance on your Mac
- On your Mac, choose Apple menu > System Settings, then click Appearance in the sidebar. (You may need to scroll down.) Open Appearance settings for me.
- Select Light, Dark, or Auto on the right. Light is a light appearance that doesn't change.
Note: To find out if your Mac supports Night Shift, see the Apple Support article Use Night Shift on your Mac. To change these settings, choose Apple menu > System Settings, click Displays in the sidebar (you may need to scroll down), then click the Night Shift button on the right.
Why wont my Mac go to sleep mode? ›
Another simple solution to the Mac won't sleep is to disconnect external peripherals. Sometimes, issues with the peripherals connected can create this problem. In that case, you need to disconnect them. The best way is to disconnect them one by one so that you can ascertain which one is causing the issue.
What are idle wake ups on a Mac? ›
Idle Wake Ups: This is the number of times a thread has forced the Mac to wake up from an idle state.
Can your Mac wake you up? ›
Set an alarm
In the Clock app on your Mac, click Alarms at the top of the window (or choose View > Alarms). Click the Add button , set the time, then choose any of the following options: Repeat: Choose the days of the week you want the alarm to repeat.
How do I get out of night mode? ›
To use Night Light on Android, go to Settings > Display > Night Light. On the Night Light screen, you can enable or disable this feature or create a schedule and adjust settings.
Is there a night light mode on Mac? ›
Make sure that your Mac meets the system requirements for Night Shift, then follow these steps: Choose Apple menu > System Settings (or System Preferences). Click Displays. Click Night Shift.
How to change from dark mode to light mode? ›
Mobile (Android):
- From the app menu, tap Settings.
- Scroll down to the header which reads Display, and tap Display Theme.
- Pick from System Default, Light, or Dark.
2016, Apple introduced a new iOS option called Night Shift. It reduces the blue light emitted by your phone/tablet's display, which should, ideally, reduce the strain on your eyes while you're using the device late at night. And basically every Android phone maker soon followed suit with a similar feature.
If your Mac has keyboard brightness keys: On the keyboard, press the increase brightness key or the decrease brightness key . To turn backlighting off, keep pressing. . If your Mac has a Touch Bar: In the Touch Bar, expand the Control Strip, then tap the increase brightness button or the decrease brightness button .
What is Apple Night Shift? ›
About Night Shift
Night Shift1 uses the clock and geolocation of your device to determine when it's sunset in your location. Then it automatically shifts the colors of your display to warmer colors. In the morning, it returns the display to its regular settings.
How long does it take for a Mac to go into sleep mode? ›
2. How long does it take for a Mac to go to sleep? By default, a Mac goes to sleep after two minutes of inactivity. Still, you can set different periods of time ranging from one minute to three hours of inactivity.
Does a Mac still run in sleep mode? ›
Modern computers are designed to go to sleep when you're not using them. When you put your Mac to sleep, the display turns off and most of the computer's activity ceases. This standby mode is designed to save power. However, your Mac is a light sleeper; a lot goes on when your Mac is not awake.
Why does my Mac take so long to wake from sleep? ›
Fixes: MacBook Pro slow to wake up
Is your Mac's battery completely drained? Is your battery damaged? Are connected peripherals draining your battery when in sleep mode? Has your screen brightness been completely turned down?
How do I turn off Dark Mode on Safari? ›
It's simple to switch it back off.
- As above, click the Apple icon on the top left of your screen and then choose System Preferences > General.
- Click Light.
- MacOS and Safari will now return to the light background permanently until you choose to switch it over again.
If you have a newer MacBook running macOS Big Sur or later, you can use the built-in blue light filter by going to "System Preferences" > "Displays" > "Night Shift." From here, you can adjust the intensity of the filter and set a schedule for when it should be on.
How do I turn off night mode on Chrome? ›
Turn off dark mode for Google Chrome
- Swipe up from the home screen to open the app drawer menu.
- Open Settings (the gear icon).
- Select Display.
- Turn off the Dark theme toggle.
How to turn off blue light on a Mac
- Select "System Preferences." ...
- Click "Displays." ...
- Toggle over to the "Night Shift" section. ...
- Check the box next to "Turn On Until Tomorrow" to turn it on; or you can set up a schedule by clicking into the dropdown next to "Schedule."
