OS X Fails to understand partitions changed in Windows

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OS X Fails to understand partitions changed in Windows

Hello all

So recently, I changed out my original hard drive for a new one, since it seemed like it may have been on its last legs.

First I did the Mac OS X portion, a simple transfer and first partitioning, and added a couple other partitions that I thought i would use.

However, I then switched to windows, and changed the partition mapping around a lot, and reduced the number, changed sizes and locations, before transferring windows over.

HOwever, this quickly became a nightmare. Upon returning to OS X on the newly transferred drive, after removing my old one, OS X and DIsk Utility FAIL to see the new partition mapping which was set under windows. It only sees the one set under OS X before that. Of course, I am not making any changes to files under OS X, and i'm typing this under windows.

Is there a way to get Disk Utility and OS X to see the new windows-made partition mapping, without repartitioning everything? This is a very nasty, inconvenient issue, and I have a feeling it could be dangerous too.

Posted on Jun 13, 2011 12:47 PM

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Answer 1

Kappy

Level 10

361,741 points

Jun 13, 2011 12:53 PM in response to Chris J Witt

Natively, there is only one way that you can install Windows - Boot Camp Assistant. However, this will only work if the drive has but one volume - the OS X volume. If you create a Windows partiton with Boot Camp Assistant, then you cannot add other partitions to the drive or you lose the ability to manage the Windows partition with Boot Camp Assistant.

With your described setup you need a boot loader that will work with multiple OSes installed. There really is only one third-party bootloader - rEFIt. Look for it at MacUpdate or CNET Downloads.

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Answer 2

Chris J Witt Author

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26 points

Jun 13, 2011 12:59 PM in response to Kappy

What I dont' understand is that at the Grey boot screen, the system selection bit, EFI seems to find the OS's just fine. The systems work just fine, Windows and OS X. What does not work is OS X's ability to see the windows made partitions. This also happens with non-boot drives for other purposes that were partitioned in windows.

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Answer 3

Kappy

Level 10

361,741 points

Jun 13, 2011 1:05 PM in response to Chris J Witt

By "see" do you mean they don't mount on the Desktop in OS X? Did this setup work before you changed drives?

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Answer 4

Chris J Witt Author

Level 1

26 points

Jun 13, 2011 1:15 PM in response to Kappy

Hello

This setup is new - My previous drive had partitions made only in OS X.

In essence, here's what happened;

In OS X, before transferring over, the new drive was made with these partitions: Macintosh HD, Linux, Dosdump, and TEMP.

Now after transferring everything, and switching to my new drive, it was changed to these partitions: Macintosh HD, Bootcamp, and Dosdump (FAT).

Windows sees these, and EFI boots and sees both the Windows and OS X partitions with no problem.

Mac OS X, however, still sees: Macintosh HD, Linux, Dosdump, and TEMP. Those are what appear on the desktop and within Disk Utility. Disk utility does NOT show unmounted drives; It shows those 4 as mounted properly.

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Answer 5

Kappy

Level 10

361,741 points

Jun 13, 2011 1:49 PM in response to Chris J Witt

Did you make the Windows partition using Boot Camp? How did you do this on your old drive? I mean how did you manage which system would boot? Were you relying on the Linux bootloader or something like rEFIt?

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Answer 6

Chris J Witt Author

Level 1

26 points

Jun 13, 2011 2:17 PM in response to Kappy

For the old drive, it was: Macintosh HD, Bootcamp, DOSDUMP (FAT). The windows partition was made with bootcamp, and Dosdump was made with Disk Utility, and reformatted to FAT16 in windows. OS X handled all those just fine. For determining which system to boot I just held down the option key at startup and selected which drive to boot from, which still works now. Startup disk preference pane also worked.

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Answer 7

Kappy

Level 10

361,741 points

Jun 13, 2011 2:29 PM in response to Chris J Witt

OK, so there was no Linux volume. And you started off with just OS X and Windows on a Boot Camp partition.

So, if you want the same setup again then do this:

1. Repartition to one single OS X partition using GUID and formatted Mac OS Extended, Journaled.

2. Use Boot Camp Assistant to create a Windows volume and install Windows on it.

3. Test that you can switch between booting each OS. (DO NOT make any changes to the partitions from within Windows.)

4. Use Disk Utility to shrink the OS X partition in order to add additional partitions. DO NOT modify the Windows partition which must remain at the end of the partition map.

5. Add however many new partitions you think you need for your FAT and Linux volumes (this would be two partitions.)

Note that once you do Step 4 you can no longer manage partitions using Boot Camp Assistant. That also means that any changes to the drive's partition structure could make it impossible to change, add, or delete a partition without having to re-partition the entire drive back to a single volume.

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