Model A1311 / Mid 2011 / 2.5 & 2.7 GHz Core i5 or 2.8 GHz Core i7 Processor

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Why does Mac OS X fail to install?

21.5 inch Mid 2011 iMac

In an effort to make the computer brand new, I decided to reinstall Lion. After a quick Google, I erased the hard drive using Disk Utility & restarted in Recovery Mode. I clicked the "Reinstall Mac OS X" option and agreed to the terms, and chose destination to install. It then downloaded a fresh copy of Lion and rebooted to the Mac OS X Installer. Less than a minute into the installation an error pops up:

"Mac OS X could not be installed on you computer.

Mac OS X can't be installed on the disk Macintosh HD, because a recovery system can't be created. Visit to learn more.

Click Restart to restart you computer and try installing again."

I've retried at least a dozen times with the same results. I know there is a solution out there, but it has evaded me for the past two weeks. Any advice would be appreciated more than you can imagine.

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2 Answers

Chosen Solution

Try installing a 10.6 system from your original system installation disk, do the updates to 10.6.8 then install Lion and update again.

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Check with Disk Utilities to see if you've formatted the drive GUID. Still failing? Do a reformat using the "write zeros" option to map out any bad blocks. This failing, your machine may still be under warranty, get a replacement drive. You are using the original hard drive, correct?


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It sounds like your boot table is corrupted. Have you run Disk Utility and reformatted the drive with the Mac OS Extended journaled format?

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When i try to partition the hard drive, it fails with the error: Couldn't unmount disk.


You may try a third party format tool to see if it can fix the drive otherwise it sounds like the disk is bad


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