Leopard Time Machine Solution for PC formatted drives

Discussion in 'macOS' started by AJsAWiz, Nov 1, 2007.

  1. AJsAWiz macrumors 68040


    Jun 28, 2007
    Found this information useful so I'm passing it along:

    The bad news is, we have discovered a Leopard-related issue that may very well throw a monkey wrench into your Time Machine. Anyone trying to use Time Machine with a previously PC-formatted drive could be at risk. The good news is, there is an easy—albeit none-too-obvious—fix. Here's the dilly-o:

    After I upgraded my MacBook Pro to OS X Leopard, the first thing I did was grab a brand-new Maxtor USB drive and format it to Mac OS Extended (Journaled) using Disk Utility, just like I had countless times before. As soon as I erased the disk, Time Machine popped up as promised, and asked if it could use the disk for backup. I said yes, and was on my merry way. Only I wasn't.

    Time Machine ran for a bit, and then crapped out after about 10GB. I went into Disk Utility and saw that although the partition was formatted Mac OS Extended (Journaled), the volume itself still said FAT32. I clicked Erase to reformat the drive, and got the format failure error you see above.

    I tried this with FAT-formatted drives from Seagate, Iomega and HP as well. Each time I saw the same thing. I could reformat the partition to Mac OS Extended (Journaled), and Time Machine would recognize it. Get Info would say that it was formatted correctly. But Disk Utility showed that the volume was formatted for PC. Inevitably, if the Time Machine backup was greater than 10GB, there were problems. Worst of all, if I dared try to format the volume for Mac, I would get the dreaded error, and the disk would be temporarily unmountable.

    Not only did I vary drives, but I tested the problem on various systems too. I tried it booting from the Leopard DVD, with the same results. Ditto when I tried it using my wife's Leopard-upgraded MacBook Pro. (Yes, his n' hers MBPs. You can insert your "awwww" here.) The end result was that I couldn't break the FAT grip on these damn drives.

    I made some calls, I talked to some people, and eventually here was the solution: you wipe the hell out of the drive by creating new and different partitions. So, do not head to the Erase tab in Disk Utility to prep a PC-formatted drive for Time Machine. Instead:

    • Go to the Partition tab. Create two partitions. Under Options, select GUID Partition Table (what you would use to make a Mac OS boot disk) and click OK then Apply.

    • Once your partitions are in place, do it again, reverting back to just one partition, but still keeping the GUID Partition Table option. Click OK and Apply again, and at this point you should be cool.

    • To be safe, you can then go to Erase and set formatting for Mac OS Extended (Journaled), then format it once and for all. But when you get there, you will probably see that your volume is already formatted in the right way.

    UPDATE: Some people have gotten this to work without creating two partitions. If you like, try creating just a single partition, but using the GUID Partition Table option. This may be all it takes to break the chokehold.

    Using this method, I have gotten all of the disks to work just fine with Time Machine, and I don't anticipate any problems in the future.

    OK, I know, quite a bit of nerdiness, but I wanted to get out there and tell you about the problem I encountered, in case you are having the same troubles, or plan on getting there sooner or later. Also, this solution is actually a workaround of sorts. My hope is that Apple can update Disk Utility with a stronger form of disk erasing that doesn't require so many manual steps, but if I am missing something obvious, I'd love to hear it. Please share any troubles you've had, or any better solutions you've cooked up.

    Special thanks to Dorian and Ken!
  2. wrldwzrd89 macrumors G5


    Jun 6, 2003
    Solon, OH
    I am aware of this issue. It is due to the partitioning scheme being set to MBR, which Time Machine doesn't get along with for some strange reason. You don't have to change it to 2 partitions then back to 1 - just changing the partitioning scheme to GUID Partition Table is enough.
  3. rowilson macrumors newbie

    Oct 8, 2008
    Is this still an issue?

    Just got a WDElements ext hd. Want to use Time Machine on my new MacBook to back it up to the ext hd. Do I need to do this formatting exercise? Thanks.
  4. Colonel Badger macrumors 6502

    Jun 30, 2008
    Yes I would, just to be sure. It only takes a few minutes to wipe the Partition table and create a new GUID table and format.
  5. cutcopypaste macrumors regular

    Nov 28, 2008
    wonder if this would be necessary with snow leopard and an ntfs formatted hd.. guess might as well...
  6. maflynn Moderator


    Staff Member

    May 3, 2009
    Kind of a long post stating the obvious, Mac users should be sure to use HFS+ format and GUID partition types. I could be wrong, but that's generally common knowledge.

    HFS+ has a number of advantages over FAT so its kind of a no-brainer.
  7. dyn macrumors 68030

    Aug 8, 2009
    Fat32 can't use files bigger then 4 GB anyway, so the problem will be at the 4 GB limit and not the 10 GB limit. As wrldwzrd89 already stated this is because the problem lies within the chosen partition scheme. In order for Time Machine to work properly make sure the drive uses the GUID partition scheme (I believe APM should work as well). You can do this in Disk Utility when repartitioning the drive, don't use the erase option. Time Machine also needs a Journaled HFS+ filesystem so make sure the partition is formatted that way (if you tell Disk Utility to set up 1 partition it will automatically do this). Snow Leopard has not changed this behaviour since HFS+ is necessary because Time Machine uses "specific" features HFS+ has and fat32/NTFS do not (one of those features is the reason why backups take up less space then you'd expect).

Share This Page