5 Replies Latest reply: Apr 1, 2010 8:58 AM by Kappy
Mia C. Level 1 Level 1 (15 points)
Hello,

We recently purchased an external hard drive for our family iMac after we had to have a new hard drive put in. We picked up a Western Digital 1tb My Book (http://www.wdc.com/en/products/Products.asp?DriveID=725). I set up the external hd with time machine and all was fine for about a month.

An error message of "The backup volume is read only" started appearing. I attempted to repair the disk through these directions http://support.apple.com/kb/HT3275#1 but when I was trying to follow the steps, I think I disconnected the external hd without dismounting it, so now I'd assume I need to reformat the external hd. I can't seem to find instructions on how to do this. Where should I look for reformatting my external hard drive?

Any other tips or suggestions would be greatly appreciated.

MacBook Pro, Mac OS X (10.5.7), iBook G4
  • 1. Re: Need to reformat external hard drive for time machine?
    Kappy Level 10 Level 10 (226,765 points)
    Hard Drive Preparation

    1. Open Disk Utility in your Utilities folder.

    2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

    3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID (for Intel Macs) or APM (for PPC Macs) then click on the OK button. Click on the Partition button and wait until the process has completed.

    Message was edited by: Kappy
  • 2. Re: Need to reformat external hard drive for time machine?
    confused K Level 1 Level 1 (0 points)
    I wanted to know if I can backup my G5 iMac and my intel macBook on the same hard drive My Book for mac. I gather from the reply here the disk requires 2 different formats?

    My original concern was whether I had to partition the hard drive for each machine. Now I wonder if it is even possible?
  • 3. Re: Need to reformat external hard drive for time machine?
    Kappy Level 10 Level 10 (226,765 points)
    To be bootable partitions they would need two different partition schemes which is not doable If you are going to install a new OS X installation. However, if you plan to clone existing systems, then you can partition the drive using APM. Clone the PPC system to one partition and the Intel system to the other. Then bot machines can be booted from their respective clones.
  • 4. Re: Need to reformat external hard drive for time machine?
    Mia C. Level 1 Level 1 (15 points)
    Thank you so much. I followed your instructions and once it finished (partitioning?) I was asked if I wanted to use that disk for time machine.

    It seems to be working fine now.

    I hate to ask such a simple question, but other then looking in time machine, is there a quick way I can check that everything has been backed up properly?

    Thanks again!
  • 5. Re: Need to reformat external hard drive for time machine?
    Kappy Level 10 Level 10 (226,765 points)
    No really. The TM application is the only direct interface to the backup. You can examine what is in a backup set using the Finder by simply navigating through it. It's on the backup drive in the Backups.backupd folder. However, you must not manipulate the backup except through the TM application.