HOW TO DIAGNOSE STARTUP PROBLEMS USING SAFE MODE

START UP IN SAFE MODE

01 To start up in safe mode, hold down Shift immediately after pressing the power key to turn on your Mac. The Apple logo will appear, followed by the login window. When seen, release Shift and log in to your user account.

CHECK AND TRY AGAIN

02 You can use Disk Utility if you like, or check installed kernel extensions in Terminal. Restart normally. If you get the same problem, start in safe mode again and go to your user account in System Preferences > Users & Groups.

RULE OUT LOGIN ITEMS

03 Note what’s listed in Login Items, then use the – (minus) button to remove them all. Restart. If fixed, press + to restore items, restarting after each one to see if the issue returns. If so, use safe mode to check for/install an update.