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Question: Partition issue, couldn't unmount disk (error)

Hi,


I have a Mac that I put a partition on a few months ago, I now want to reformat. Yet when I go to my Recovery HD on Lion then to Disk Utility and try to format my HDD it gives me an error saying it couldn't unmount disk, the two partitions on the HDD unmount but the HDD does not. So I googled it and read a few soulitions however the most common one creating a bootable drive with the Recovery HD on it dosen't work either. One of the soulitions I saw was installing Linux on a removable drive and formating the drive from their, however that seems inpractical for what I'm trying to accomplish, if anyone has a fix for this it would be greatly apreactited.


Thanks.

MacBook Pro, Mac OS X (10.7.3)

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Apr 22, 2012 4:39 AM in response to goldish In response to goldish

It sounds like you're trying to partition the drive. You can't do that while booted from it. You would have to boot from another device, such as a Time Machine backup drive, Lion Internet Recovery, or a USB drive prepared with Lion Recovery Disk Assistant.

Apr 22, 2012 4:39 AM

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Apr 22, 2012 4:52 AM in response to goldish In response to goldish

In DU on the partition tab highlight the last partition and click the Minus Sign. Then expand the first partition to include the whole drive (bottom right hand corner). Then go to the Erase Tab and select the new expanded partition then click erase.


NOTE:

You must be booting the computer from the Recovery HD partition, a USB stick with the Recovery HD partition files on it, Internet Recovery system or a OS X install DVD to do this.


You can not select the complete, physical, drive while booting the computer form any of it partitions.

Apr 22, 2012 4:52 AM

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Apr 29, 2012 5:25 AM in response to Shootist007 In response to Shootist007

this is basically what happens:


http://forums.macrumors.com/attachment.php?attachmentid=220484&stc=1&thumb=1&d=1 270222347


this is not a screen shot I took but thats the same error, all I'm trying to do is make my HDD un partitioned, I can't do it in disk utility... when I have a partitition I can't set up boot camp which is really annoying ..

Apr 29, 2012 5:25 AM

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Apr 29, 2012 5:31 AM in response to Linc Davis In response to Linc Davis

I partitioned my HDD (boot camp) then I decided last week to reinstall the OS (because I noticed things to be a little slow)


when I tried to reinstall in the Recovery HD, it gives me an error saying that I need to unmount my HDD


I go back to diskutil still on the Recovery HD and try to unmount but it just gives me the error :


"Partition failed with the error: Couldn’t unmount disk."


if I try to click the - on the partition tab or do anything else


"Partition failed with the error: Couldn’t unmount disk."


thats it..


what do I do?

Apr 29, 2012 5:31 AM

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Apr 29, 2012 9:11 AM in response to goldish In response to goldish

When asked for an exact description of what you're trying to do, you posted only a screenshot that shows an attempt to erase a volume, and an error message different from the one you've been reporting. That conflicts with your verbal description. Every message from you in this thread says something different. When you can come up with an exact, complete, consistent description of the problem, please post it.

Apr 29, 2012 9:11 AM

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Apr 29, 2012 11:27 AM in response to Linc Davis In response to Linc Davis

Linc you can change, resize, and add partitions when booted into the OS or from the R-HD or from booting from an install disc using Disk Utility.


User uploaded file


You have to use the resize arrow, in red bottom right corner, to drag the existing partition up, resizing it, then create a new partition from the space left over.


You can't use the Partition drop down, in Yellow.

Apr 29, 2012 11:27 AM

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Question: Partition issue, couldn't unmount disk (error)