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My new macbook pro installed two systems: Mac(10.7.1 Lion OS) & Windows(bootcamp).

I cant't startup from mac because of the power outage yesterday, but I can enter into windows at this time by restart and hold "Option". And chose "Bootcamp" from the 3 disks: Macintosh HD","BOOTCAMP" and "Recovery HD".

But when i try to reinstall mac from Recovery HD. It can't.So i thought it's bootcamp partion's problem, then i tried to delete "Bootcamp" partion via "Disk Utility". But the error always " Partion failed with the errr: Couldn't unmount disk.

Help! Thanks very much!

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migrated from Jan 16 '12 at 17:48

This question came from our site for professional and enthusiast programmers.

See, Windows is a virus that can harm your computer. But in any event, you have to choose "Macintosh HD" to boot after holding "Option". If that doesn't work - locate your OS X recovery CD, or installation CD, and boot from CD to recover. Do not delete any partitions or say good bye to your data. Just in case you have Time Machine backup drive, you can choose to restore the whole system image, and it will probably be like 20 minutes old system since you last used it. – user49531 Jan 16 '12 at 16:32
@VladLazarenko I chose "Machintosh HD" at the beginning, but just the gray screen with apple logo and a spinner. There's no recovery CD, but only "Recovery HD" which instead of installation CD right now. I don't have Time Machine backup. I just don't understand 1)why i can't delete "BOOTCAMP" partication via Disk Utility. 2) Not sure it's because of "BOOTCAMP", i can't reinstall it via "Recovery HD". Thanks your quick answer! – William Hu Jan 16 '12 at 16:50
@WilliamHu: Your best option right now is to simply call Apple's support and hang on the phone. Or bring your book to the Apple Store. – user49531 Jan 16 '12 at 17:13
@VladLazarenko: yeah, i will call tomorrow and try some other ways tomorrow. Thanks! – William Hu Jan 16 '12 at 17:26
When you tried to install Mac OS X from the Recovery HD, what was the exact error? Try resetting the PRAM. – fideli Jan 17 '12 at 1:52

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