Open System Settings
Click Lock Screen
Set “Turn display off on battery when inactive” to Never
Set “Turn display off on power adapter when inactive” to Never
Open System Settings
Click Battery
Turn off “Put hard disks to sleep when possible” if available
Turn off “Slightly dim the display on battery” if needed
Open System Settings
Click Displays
Increase the display sleep time if available
Open Terminal
Run `caffeinate`
Run `caffeinate -d`
Run `caffeinate -i`
Keep the Mac plugged into power
Prevent the lid from closing if you want it to stay awake
Check for scheduled sleep in System Settings
Quit apps that may trigger sleep or display dimming
Restart the Mac if sleep settings do not apply