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Disk Utility refuses to partition. (Help!)

S

Sergeant Pepper

macrumors member
Original poster
Jan 28, 2009
93
0
OK, I'm trying to partition my hard drive. It's currently one whole 160 GB unit. I want to split it into a 135 GB partition and a 25 GB partition.

Currently Used Disk Space: 95.10 GB
Currently Free Disk Space: 53.51 GB

However, whenever I try to create the 25 GB partition in Disk Utility (formatted as Mac OS Extended - Journaled) it gives me an error message:

partitionfailed.png


And here's a screenshot of my hard drive's info:

harddrive.png


What's going on here?
 
I've never done this, but, as a guess, I'd say you need to change the size of the original partition before you can create a new one - i.e., the current partition uses up all of the disk.
 
Aha. That makes sense. Attempting to fix that now.

EDIT: OK, I tried resizing the current partition to 135 GB, which would leave 25 GB of free space which I could then format, but I got the same error message. Which makes absolutely no sense, because I have over 50 GB free on this stupid thing.
 
Have you ever used boot camp? I think the issue might be if you did, there were some files left and it's not letting you partition because of that. From my understanding (and I may be wrong) when OS X is partitioning, it is looking for 25 GB of continuous free space. So if there is a random file or something it'll get in the way and it'll say you don't have enough free space. I've had this same issue and what I did was defrag my hard drive to clean up those random files and I was able to partition what I wanted, although I still can't make a partition larger then ~20 GB. I dunno if you have the same issue as I did, but I am interested to see if there is a fix out there.
 
First off as your Get Info window shows the actual usable space on your drive is not 160Gb but is actually 148Gb which is normal with the way drives are marketed. The reason I bring that up is that to have a 25Gb partition on your drive, the other one would need to be 123Gb, not 135Gb.

Secondly, my bet would be that this drive is one that came formatted for PC, but was then erased in Disk Utility to assign it a Mac OS Extended format. The problem with that is that doing that gives the space on the drive a Mac format, it leaves the Partition Table Map as MBR (which is a PC partition table that you cannot change partition sizes on non-destructively in Mac OSX). The complete method for prepping a PC formatted drive includes establishing the Mac type of partition map as part of the process.

Try this in order to check that- open Disk Utility and click on the drive name in the left column to highlight it. Click the "whole drive" line there, not the partition line below it. Check out the information at the bottom and see what it says for "Partition Map Scheme:". If that reads MBR (or Master Boot Record), you can not non-destructively change partition sizes on the drive as it is not fully "macified". If it reads "GUID Partition Table" there already, then I lose my bet!;)

To set up a GUID partition table map for the drive if it needs one, the drive would need to be erased in order to do it unfortunately, but partitions afterward could be resized "on the fly".
 
sickmacdoc said:
...this drive is one that came formatted for PC...
Click to expand...

I would be really worried if that were the case, since this is the internal HD that came with my MacBook.

EDIT: And to lostfan916, I've never used Boot Camp. Thanks for the thought, though!
 
Sergeant Pepper said:
I would be really worried if that were the case, since this is the internal HD that came with my MacBook.

EDIT: And to lostfan916, I've never used Boot Camp. Thanks for the thought, though!
Click to expand...

Yeah, that could be a problem then and I lose my bet.:(

Have you tried doing your partitioning via the Disk Utility that is available when booted to the OSX installer disk? While Leopard should be able to resize the boot partition even on the booted drive (which I just did to confirm) that would eliminate one more source of possible problem. It would also give you a chance to run the "Repair Disk" function if necessary on the drive before partitioning since you can't do that on the booted disk in DU. Good luck!
 
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