Amphetamine keeps your Mac awake by applying system power assertions: one to keep your display awake (optional), and one to keep your system awake (required). You can confirm that the assertions have been applied during an active session by using a Terminal command.
1. Launch Terminal.app from /Applications/Utilities
2. In the Terminal window, type the command: pmset -g assertions | grep "Amphetamine"
The output of the command should look something like this:
Note that if you’ve configured Amphetamine to allow your display to sleep, you will only see one line/assertion returned.
My Mac Still Sleeps!
If your Mac is falling asleep even with one or both of these power assertions applied, one of the following may be the issue:
1. Is your display falling asleep?
If your display falls sleep, it can appear as if your Mac has fallen asleep. In fact, display sleep and system sleep are two separate sleep modes. Of course, in order for system sleep to occur, display sleep must also occur, so it can be a bit confusing.
Ensure that Amphetamine is not set to allow display sleep. This option is found in Amphetamine Preferences → General → Allow Display Sleep. If you're using Triggers, each Trigger has its own display sleep setting. Visit Amphetamine Preferences → Triggers and double-click on one of your Triggers. The Trigger Configuration window will open. In the Trigger Configuration window, ensure that Allow display to sleep when this Trigger activates a session is unchecked.
One other thing to check is your Mac's Security & Privacy settings. Depending on these settings, and whether you allow your display to sleep, it may appear that you Mac is asleep when in fact is is not asleep. If your Mac is set to require a password after X minutes of display sleep, that does not mean your Mac has fallen asleep. Visit → System Preferences → Security & Privacy → General and change your Mac’s settings if desired.
2. Is your Mac configured to log out after a period of inactivity?
Visit → System Preferences → Security & Privacy → General → Advanced to check whether your Mac is set to log out of your user account after a period of inactivity. Note that the Advanced button may be locked. To unlock it, click the padlock icon and enter your password.
3. Is Amphetamine installed in the correct folder?
Make sure Amphetamine is installed in the /Applications folder. While it might be convenient to move Amphetamine to your Desktop or another location, apps from the Mac App Store can encounter odd issues when moved outside of the /Applications folder.
4. Are you closing the lid of your Mac (clamshell mode)?
Apple has very strict requirements for using a Mac in clamshell/closed lid mode. If you're not meeting these requirements and are expecting Amphetamine to keep your Mac awake while its lid is closed, think again. This feature has never been supported despite what some of the reviews on the App Store might state.
For more information about this, click here.
5. Is your Mac already asleep?
Amphetamine cannot wake a Mac that is already in a system sleep state. Amphetamine’s Triggers feature does not work when your Mac/system is asleep.
6. Does the issue persist while logged in to a different user account?
A good way to isolate any issue is to try to replicate it under a new user account. Instructions for how to create a new user can be found here. If you find the issue does not persist under a new user account, you can log back in to your user account, skip step #7, and proceed to step #8.
7. Reset your Mac’s SMC
If your Mac is definitely falling asleep while Amphetamine should be keeping it awake, try resetting your Mac’s SMC. If your Mac is not respecting the power assertions applied by Amphetamine, no amount of resetting, reinstalling, updating, etc. Amphetamine will solve the issue. The only solution can come from Apple in a macOS/firmware update, or through resetting your Mac’s SMC. Check out this Apple support article for a step-by-step guide:
8. Delete Amphetamine's Preferences
If nothing else has worked and Amphetamine still isn't working properly, you can try deleting Amphetamine's preferences. First, quit Amphetamine, and then open up a new Terminal window.
Note that deleting Amphetamine's Preferences will result in you losing all Triggers, custom icons, custom durations, and all other configuration.
How to Reset Amphetamine's Preferences
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