Blog by an Apple Certified Tech

iMAC NOT BOOTING UP

Turning off after spinning wheel/beachball/processing icon

Exact issue that you might face: The machine will turn off after spinning beach ball.
Before I mention the troubleshooting steps, let me explain the reason in brief. Mac has given a new feature in Leopard that enables the functionality to perform a disk check in the back ground and occurs at every start up. Now while performing this check if there is any irreparable damage then it shuts down the mahcine.
If you face this issue all you have to do is using Mac OS X installation DVD boot the Mac from another volume/drive and then use the disk utility feature to verify if there is any issue and see if it could be repaired. If its irreparable then reinstall the OS using erase and install.

I would recommend you to copy the data on another volume and then install the OS on this drive.

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