Disk Utility defaulted to Logical Volume Group format for new 4TB HDD and won't let me change to GUID. Is that a problem?

To speculate, I would guess that Apple changed Disk Utility to accommodate fusion disks and, in doing so, screwed things up.

There is anecdotal evidence that this was caused by an attempt to accommodate WINDOWS drives over 2.2TB.

Also, the labs at Apple may be populated with black cylindrical Mac Pro prototypes, so there may have been few opportunities to test Internal Drive issues. External Drives work fine.

SOLUTION:

I have experienced the same problem that others have here. I have an Intel MacPro in which I recently installed a new internal 3TB hard disk.

I attempted to format it in Disk Utility under OS X Mountain Lion (10.8) using standard GUID partitioning. But disk Utility formatted it using a Logical Volume Group (LVG) instead of GUID.

Disk Utility subsequently refused to allow me to reformat or repartition this drive. Ithought I was stuck with a LVG drive.

For the solution that worked for me see the answer by GrowlTiger at AskDifferent

Using the 10.6.3 DVD was suggested above. ANY DVD or system disk that predates 10.8.4 should work (provided your Mac can actually boot from it). or an external enclosure.

@Grant

Yes, I read the entire thread, and several others here.

I tried 10.8.3 and it didn't work in my situation. When booting from 10.8.3 the Partition Layout drop-down was still greyed-out in Disk Utility.

My solution uses the 10.6 DVD because it's the last universal DVD that is available from 10.6 to 10.8. This was a convenient bootable source for me, and I assumed it would be so for others who don't have multiple bootable copies of historical OS X versions readily available.

Unfortunately, the Mac Pro 2010 cannot boot from the 10.6.3 "Full Retail" DVD. It shipped with a custom 10.6.4. The 2012 model shipped with custom 10.7.3 and no DVD.

First, let me say that I am astounded that this problem exists. I have had more problems with OS X 10.8 than I have had since OS 9.

Second, I want to confirm that you can properly format the drive in earlier versions of OS X. Luckily all of the drive bays are occupied in my Mac Pro and I have abandoned versions of 10.5.8 and 10.6.8 (which are like a time capsule of what my Mac looked like years ago whenever I boot in them). I booted into 10.6.8 and formatted the drive without a hitch.

Condolences to those of you who are being hindered by this issue. Has anyone heard Apple's excuse for this?

it was a Bug introduced, probably in 10.8.4, while attempting to fix "over 2.2TB drive size" for Windows.

Frank Lowney wrote:

Here's the solution that worked for me. I booted into MacOS X 10.7 from an external disk, launched Disk Utility from there and noticed right away that disks that were seen as Logical Volume Groups under 10.9 were seen as GUID volumes under MacOS X 10.7. The names of the disks were correct and everything looked as I would have expected. Even the disk names were back to their originals. They had been changed to the name of one of the partitions when I erased the partition and changed that name under 10.9...

In the extensive discussions of the big drive Disk Utility bug in Mountain Lion and Mavericks, the focus has been on what happens when formatting and partitioning a 3TB or 4TB drive in an internal bay, usually of a Mac Pro.

But as you've found, a properly set up HD (SSD's are too small to be affected, as are externals, which may be why any fix is on the back burner) can be damaged by simply erasing one partition.

After installing a second SSD in a 2010 Mac Pro running Lion, I cloned the boot partition to the Crucial M500 and upgraded it to ML. There are also two 3TB internal HD's and one of them has the Time Machine partition on it. Wanting to start over with TM for the ML boot drive, I erased the TM partition using ML's Disk Utility.

That HD immediately became a Logical Volume Group with the name "Time Machine" replacing the usual media line and the TM partition jumped from last position to first. Also on that HD are Snow Leopard and Lion partitions and they can boot normally. Booting from the Lion SSD, Disk Utility doesn't show any of these changes, which is to be expected.

The take-away from all this is that simply erasing an otherwise properly configured partition in a properly formatted 3TB or 4TB internal HD with ML's or Mavericks' Disk Utility can change the nature of that HD in ways whose long term effects I don't think we yet know.

There turns out to be a solution to this which doesn't require rebooting or removing the drive. So long as you haven't put any data on it -- you actually can use the command line version of Disk Utility to fix it.

First run diskutil cs list to get the UDID of the volume group and the logical volume. Then you just delete teh volume and the group that was created when Diskutil did the bad 'erase' -- when you do that, your drive will be left with a single clarge partition and you just don't use Erase after that - use Partition in Diskutil and you'll be all set.

The commands are:

diskutil cs list

diskutil cs deleteVolume <Logical Volume UDID>

diskutil cs delete <logical volume group UDID>

BE WARNED - if you have a fusion drive, this will also show up as a Logical Volume Group and you need to make sure you're picking the right ones or you'll have serious data loss. The command line is unforgiving.

I was very happy to not have to dig up a CD or take the drive out. Hopefully this helps someone else.

SnipperJS-

Thank you for that very straightforward recipe for fixing this problem with Terminal diskutil commands. For Users willing to use Terminal, this seems like a good way to proceed.

These <logical Volume UDID> what do they look like? are these like "disk2s3" designations?

Great question!

Mine look like:

Logical Volume -> 615BA501-6898-45FF-9822-6DB4B4F52268

Logical Volume Group -> 96864B74-C0C4-4493-A15C-14710B1E64CE

I used two terminal windows -- one for the list and one for the deleting.

You can cut-and-paste those big strings, right?

SnipperJS wrote:

...I was very happy to not have to dig up a CD or take the drive out. Hopefully this helps someone else.

But you still have to boot from a Lion or earlier partition/CD installer to erase a partition without damaging the other contents of the affected drive?

Yes, you can cut and paste from the terminal window.

You can't save anything on the drive no matter what you do -- you have to remove everything and then do this process.

Basically the bug has to do with Apple expecting everyone to have an iMac or Mac Mini and wanting a fusion drive. Their testers totally forgot about us Mac Pro users. So Disk Utility by default when you put a large drive in, creates a logical volume group -- basically that's the basis for a fusion drive.