Lot of iMac users reported this issue. Late 2010 27 inch iMac shut down randomly by itself. It does not restart automatically.
Solution 1: Uncheck “log our after?? minutes of inactivity”
This problem not happened because of your iMac system. This issue happened because of the Security and Privacy preferences in Apple System Preferences.
- Launch Apple menu-> System Preferences.
- Click “Security and Privacy control panel”.
- Choose the “General” tab.
- At the bottom of the screen, click Advance button. If the button is grayed out, click the lock button and enter your login password.
- Untick the check box “Log out after ?? minutes of inactivity”
- Click OK
- Now exit the control panel.
Solution 2: Delete “com.apple.PowerManagement.plist” file
- Navigate to Library ->Preferences ->SystemConfiguration.
- Delete file named com.apple.PowerManagement.plist.
- It may ask your administrator password to move the file to trash.
- Restart iMac computer
Also Read : Fixed : iMac and MacBook Pro stuck on “setting up your Mac”
Solution 3: Check your display
Adjust your iMac displays brightness to lowest setting as possible (adjust the brightness level to see the screen). If your system staying up and running longer time before? then your display has a issue.
Solution 4: Check numeric code followed by “Previous shutdown cause:”
- Go to your Mac Utilities folder and open console.
- Inspect system.log file for shutdown cause.
If you knew any other solutions to fix ” iMac Shut Down Randomly by Itself” problem, inform us using comment form.