#Fixing a mac pro power supply mac os x#

#Fixing a mac pro power supply mac os x#

This can indicate a corrupt installation of Mac OS X or a failed (or failing) hard drive.ДЄ pass through the excellent DiskWarrior utility is highly recommended for any disk-related startup problems. The flashing question mark or a circle/slash means your Mac canвЂ™t find a valid startup disk. Leaving a failing drive struggling too long can cause further damageДЇlashing question mark with folder, or circle/slash

Sometimes switching on/off a few times can help, but donвЂ™t push things under these circumstances. This can indicate a failed or failing hard drive. Sometimes a Mac will power on but the hard drive will squeal, whine very loudly or make ticking sounds. If your Mac doesnвЂ™t make any noise at all when switching it on, or if you hear the fans running but nothing else, you may again have a power supply or logic board failure. Listening to your computer may seem a bit metaphysical, but can provide helpful clues to startup problems. Sometimes plugging in the computer and letting it sit for 30-60 minutes recharges the battery enough to permit booting. A dead or dying PRAM battery can prevent a Mac from booting or cause erratic behavior. If the date and time reset each time you unplug the Mac you need a new PRAM battery.

Macs also have another battery, called the PRAM (or NV-RAM) battery, that saves things like network settings, choice of startup drive, etc.