For our latest products, please visit the OWC website at

FAQ - Frequently Asked Questions - Knowledge Base

Cannot format external hard drive on Mac OS 10.5!

If the formatting process on Mac OS 10.5 has failed but the drive has been successfully formatted on a PC or another computer previously, try following:

  1. Open the disk utility and select the external drive.
  2. Choose "1 Partition" from the volume scheme and then click on "Options".
    Disk Utility
  3. Select "Apple Partition Map" and click OK.
  4. Apply these settings to format the drive. After successfully formatting it, create as many partitions as you like and feel free to go back to Options to select a different partition scheme.