Rebooting your Mac in Safe Mode can sometimes get things working well-enough that a second, normal reboot then works normally Hold down the Shift key at startup to boot in Safe Mode. It may also be having trouble accessing an internal or external hardware component, but this is less-likely. What this means for us mortals is that when a Mac stalls at the Apple logo or the logo with a spinning gear, it probably has a corrupt Mac OS X installation. Shortly thereafter it transfers command to the almighty (and controversial) launchd process. Once the spinning gear appears the BSD kernel (Darwin) has assumed command and begins loading device drivers.

When the Apple Logo appears your Mac has found a valid system disk, and Mac OS X begins loading. You can also try Apple Disk Utility or another third-party utility like TechTool Pro or Drive Genius to try to repair the disk. If the drive is OK after repairs but the Mac still won’t boot, do an Archive & Install of Mac OS X to replace the operating system. This can indicate a corrupt installation of Mac OS X or a failed (or failing) hard drive.Ī 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 can’t find a valid startup disk.

Leaving a failing drive struggling too long can cause further damageįlashing question mark with folder, or circle/slash Sometimes switching on/off a few times can help, but don’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 doesn’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.

Mac os x boot disk not found