Reset your PRAM

Reset your PRAM

This maneuver gets its own section only because it’s one of the oldest troubleshooting techniques in Mac history. PRAM (parameter random access memory) is where your Mac stores many of its hardware settings. Resetting the PRAM almost never resolves a startup issue, but it’s something Apple support usually asks you to do when troubleshooting a problem (and it does, in some rare cases, help). To reset the PRAM, turn on your Mac,immediately press and hold Option Command-P-R, and continue to hold those keys until your Mac restarts and your hear the startup chime a total of three times. After you do this, you may have to reconfigure some of the system settings (like date, time, and possibly keyboard/mouse settings if you’ve customized them).