Wednesday, February 18, 2009

Disk Utility Erase Failed on Mac OS X

Ok, I'm always running out of hard drive space. I just bought a $100 one terabyte external USB 2.0 and eSATA drive to add to my current pile of external hard drives.

Of course it ships formatted FAT32 which Mac OS X can read, but isn't a very good format (doesn't support journaling, limits file sizes to 4 gigs, etc.) So we need to erase and format the drive (or partition or reformat... whatever you want to call it.)

No problem. I launch Disk Utility, select the new drive, and click the Erase tab. Then I select Mac OS Extended (Journaled) as the Volume Format. Then I click Erase. It warns me I'll delete data, blah blah. It starts erasing, and then says the erase failed. Specifically it says:
Volume Erase Failed with error: The underlying task reported failure on exit

After a few more tries I found the solution and it requires changing a setting in the partition. We only want to create a single large partition but we still have to change a setting in the Partition tab.

If you don't see a Partition tab between Erase and RAID try selecting the drive in the list to the left. You may have selected the mount point (or sub volume/partition). To edit the partitions you have the have the higher level drive device media selected.

Ok, after that, click the Partition tab, then select 1 Partition from the Volume Scheme drop down menu. Then click the Options button. Chances are Master Boot Record is selected. You don't want that for a Mac OS Extended format drive. Instead select the GUID Partition Table and click OK (You only want to choose the Apple Partition Map if you are running on a PowerPC Mac with an OS below Mac OS X 10.4 or if you are running a PowerPC Mac and you need the disk to be a startup disk.)

Then click Apply. That should do it.

UPDATE:
I haven't been able to reproduce this problem since the Mac OS X 10.6.3 update. If you have this issue and you are running 10.6.3 or newer could you please let me know with a comment below? Thanks!

64 comments:

Frank Martini said...

Same exact problem here w/ a 1Tb Seagate FreeAgent drive. Thanks for posting this. You saved me a LOT of time figuring it out.

Araware said...

Thank you -- just save hours of my time trying to figure this out. Changing the options to GUID helped solve my problem.

Sniggy said...

Thank you thank you thank you thank you.

Had the same problem with two 1TB WD Elements drives. I was about to conclude that there's something wrong with them. But two defective drives at the same time strains credulity, and I'm happy to find the explanation here.

monika said...

Thanks so much for this tech support, was about to throw the drive against the wall before I found this. You are a life saver. Thanks!!!

lyra895 said...

You are a hero! Thanks for this

HÃ¥var said...

amazing, thank you so much!

tonydasinga said...

If I could love a man...

Larry said...

Sweet. Mac fails this ease-of-use test, which is rare.

Aric said...

Uh, thanks Larry. It's definitely a bug in the software and shouldn't behave that way. I can't remember if I've submitted this one to Apple. I have several outstanding bugs submitted to Apple.

Justin said...

Thank you soooo much. I just bought a quad interface 1TB drive as well. I was almost about to reinstall my os thinking that the NTFS-3G system preference has somehow corrupted my computer when a friend removed his Windows formated drive without ejecting it first.

You have saved me so much time, again, thank you.
Now to trouble shoot my Time Machine drive.

Matthew said...

Thank you so much, that was incredibly helpful.

Jeff said...

Another thanks. I was having the problem with a 1.5Tb Seagate. This did the trick, and saved me a lot of time.

Vic Rubba said...

you saved my bacon! thank you!

HellCat said...

Oh my goodness, I had never seen this problem before on a drive and Boom! This post solved it. Thank you so much!

socalled somebody said...

THANK YOU. I've formatted dozens of drives and never had that problem before. Your post saved me from sending a drive back!

princeword said...

dude, I looked through several solutions last night, one that took me 9 hours, but ended up only formattingt he subdisk and not the full drive (which made it unreadable) and with your solution, it took 3 seconds, damn!!

Thank you so much!!!

cheers

MrsPeel said...

THnaks SO MUCH!!!!! for posting this.
I bought a 1TB Seagate FreAgent Desk, and after going through many methods post in the mac's forums, a friend who was on the fone with me googled and we found you. I have to admit I wasready to give up and box everything and try to exchange it, as I have another 500GB Seagate which had worked wonderfuly on the Mac....
You saved my blood pressure, my panick attack and a lot of sweating with Amazon,
my teenager daughter thanks you too!
:)

sybille.sorrentino said...

Thank you so much!!!!!
First, disappointedly, I did exactly what you said to do with a hitachi simpledrive 1 TB. Perhaps I tried too many other things first? maybe I tried to use the Time Machine before erasing? Whatever I did didn't allow me to partition or erase.
I tried again with a second drive (the same make and model) and it worked perfectly.
Thank you so much for sharing this with us. I still don't know why it didn't work on the first one?
Thanks a million!

Benjamin said...

Honestly thank you is not enough. I cant find words for what this small article has done. This was freaking me out and in about 5 seconds you solved my issue.

*daisy said...

you are my hero! Thank goodness your blog came up in a quick google search- thought I was going crazy!!

Robert said...

Wonderful!
Thanks so much, saved my a&&.

robert

Dr. Justin Nystrom said...

Hall of fame answer!

Jason said...

Thanks so much! Same issue with 1TB Seagate here!

Gav said...

Awesome! Many thanks for this fix. Just bought a 1.5TB WD drive and was wondering what was up. All good now. Cheers!

unilooney said...

Got given a Seagate drive as a present, couldn't figure out why it wouldn't work. Serious kudos, mate!

Sean Benson said...

Thank you for this, this is exactly what I needed to know. I bought a Seagate terabyte that was 'For PC', and I have a mac, and was getting worried that it wouldn't work. But problem solved.

bradhebert said...

Thank you! Last time I called tech support and had to connect my drive to a PC and do a bunch of stuff that was apparently completely unnecessary. This time I googled and found your post. Worked perfectly!

fallingman said...

Had same problem with a new Hitachi drive - thank you so much for the tip! :-)

S.B. said...

thank you!!! randomly googled and this worked!

fastfinger said...

hooked up old PC drive to mac via external cradle - and firewire - was able to read files from old HD but of course not alter them or delete them. Used MAC DISK UTILITY to erase drive now nothing works with it - not a partition, nothing - isn't recognized on disktop or nothin' - I'm screwed.

Brian said...

You are awesome! And I love you. I was having this problem with my new Seagate FreeAgent GoFlex Desk 2TB external hard drive (USB 2.0). I'm running Max OS X 10.5.8 on a 24" iMac. I tried over and over to reformat to Mac OS Extended (Journaled). No luck. But after doing what you said, everything worked fine. Thanks again.

Cheers,
Brian

Brett said...

That was a HUGE help. I've had this Fantom Drive sitting around for 2 years not being able to use it. Almost spent $50 to have a guy reformat it and thought I'd give Google one last try. Your did it! THANK YOU!

Fearless said...

Thanks Buddy!!

I have Mac OS 10.6.6 and still had this problem. Reminds me of the old PC partition days...

Gus said...

Mac OS X, 10.6.6;2 GHz Intel Core Duo; 2 GB 667 MHz DDR2 SDRAM + 500 GB Western Digital external disk drive.

Similar problem ... wanted to do full back up, but not enough space on disk. OK, we'll erase the partition and rebuild it.

Attempted to erase partition
Log displays:

2011-03-19 22:18:13 -0400: Disk Utility started.

2011-03-19 22:18:39 -0400: Preparing to erase : “MacBookPro” MacBookPro is the name of the partition, not the computer itself!
2011-03-19 22:18:39 -0400: Partition Scheme: Apple Partition Map
2011-03-19 22:18:39 -0400: 1 volume will be erased
2011-03-19 22:18:39 -0400: Name : “MacBookPro”
2011-03-19 22:18:39 -0400: Size : 249.92 GB
2011-03-19 22:18:39 -0400: Filesystem : Mac OS Extended (Journaled)

2011-03-19 22:18:39 -0400: Unmounting disk
2011-03-20 06:40:04 -0400: Volume Erase failed with the error:

Could not unmount disk
2011-03-20 06:40:05 -0400: Erase complete.
2011-03-20 06:40:05 -0400:

Now I cannot get the OS (Disk Utility or Filer) to even recognize the external drive is there.

Any thoughts?

FLUX Business Communications said...

Great post. Thanks pal.

Sergej said...

Thank you. This is what i need.

Sandor Benko said...
This comment has been removed by the author.
Sandor Benko said...

Thanks for posting this! I knew the option was there but couldn't find where on my own, haha!

Steadinan said...

Wow! That's so awesome that you were able to help so many people. Unfortunately, I wasn't one of them. :(

I got the "unable to unmount" error, and it wouldn't do anything after that. I searched all over for the firmware update that's supposed to be on Samsung's website. Seagate and Samsung merged and so no more Samsung website and NO MORE SAMSUNG SUPPORT! So I'm returning my drives.

Jaunty said...

Thank you! Clearest explanation I found of this problem.

Mark said...

Thanks so much!

Mark said...
This comment has been removed by the author.
Ethan said...

Thanks alot!!! worked for me

William Noetling said...

Thanks so much for this, I was having the exact same problem and you're a life-saver

William Noetling said...

Thanks so much for this, I was having the exact same problem and you're a life-saver

Darren DeSilva said...

Thank you. That was the problem!

JoyLuck said...

Hi I'm super clueless, but had this problem and did the partition thing you suggested which totally worked - Thank you! Now, my question is do I need to go back to the erase tab and do the erase thing again or will that mess up what I just did with the partition? I notice that now when I go back to the erase tab the volume is already showing as "mac os extended (journaled)."

JoyLuck said...

Hi I'm super clueless, but had this problem and did the partition thing you suggested which totally worked - Thank you! Now, my question is do I need to go back to the erase tab and do the erase thing again or will that mess up what I just did with the partition? I notice that now when I go back to the erase tab the volume is already showing as "mac os extended (journaled)."

HanSagan said...

thank you. similar issue here with 1Tb Seagate FreeAgent drive. definitely fixed it!

Patricia Camacho said...

definitively useful information, I solved the problem II had in my computer.


















gtech hard drive for mac

BeAShowstopper said...
This comment has been removed by the author.
BeAShowstopper said...

I am having this same problem on my 2012 iMac running OS 10.7.4

I am following your instructions however I cannot get rid of the error.

Tues, 9/11/2012

Thanks for your timeless post!

Rob Overtoom said...

Thanks a lot! Seems to work for me.

Stuart Bell said...

By "Running out of space" , what I understand is lack of free space in drive.Is it necessary to delete a partition to create free space on drive? I believe, this can be done with Stellar Speed Up Mac, a Mac cleaner to delete all unnecessary stuffs from the drive.

Stuart Bell said...

For details visit: Speed Up Mac

Marc Hudon said...
This comment has been removed by the author.
Marc Hudon said...
This comment has been removed by the author.
mahasiswa teladan said...

hi...Im student from Informatics engineering nice article,
thanks for sharing :)

Kaylin Kuhn said...

Just purchased a Seagate Backup Plus 1 TB. Followed all your instructions on my Mac OS X version 10.7.5 continue to get error. Partition failed: Couldn't unmount disk. Any other suggestions?

Andrew Ferguson said...

I have been looking for a fix since last night and I wanted to know if this is similar:

I have a powerbook g4 1.5ghz with 2gb of RAM. Just purchased the OS X 10.5.8 install disks off eBay to take is from osx10.4 to 10.5. When I placed disk 1 into the powerbook, it begins to do the install by asking me to select the language. Once I select English/US it begins to load and after 4 seconds an error message pops up that says, "Unable to install osx 10.5.8 onto this computer." So, I went into the disk utility and the error message about "underlying task reported failure on exit" BUT the kicker is is that it is only reporting it on the INSTALL DISK and NOT the HD. Any ideas what the issue is?
Thanks,

Aric said...

Andrew I don't think your problem is related to the issue I describe. it's hard to say what could be causing that. I am curious if the 10.5 disks you bought are the retail ones or if they are the gray "restore" disks that came bundled with a Mac? The bundled disks will only install on the model they shipped with.

Henry Gill said...

Mac is Best operating system but inspite there are many adverse reasons that leads to data deletion from Mac drive. I too encounter same issue but thanks to Mac Data Recovery Software using which I was able to recover data.

abhay karki said...
This comment has been removed by the author.
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