5 Replies Latest reply: Oct 21, 2013 8:49 PM by Tlix
MrsWeir Level 1 (0 points)

I reformatted my I mac due to it being extremely slow. After reformat, the toshiba external hard drive that I have been using for months before with no problem, is now a read only. I have over 1TB of space available and I need to use it. Does anyone know what happened and how to fix it. I cant lose my information.

OS X Mountain Lion (10.8.3)
  • Tlix Level 4 (1,420 points)

    If the external hard drive is blank you can try reformatting it. But it sounds like it might be in Windows NTFS. Did you have third party software on your Mac previously that allowed you to read NTFS drives?


    Checked Disk Utility to see what format the external hard drive is in.

  • MrsWeir Level 1 (0 points)

    NO I didn't have a third party software before. What would I need now to make it work. I need the HD working if it is in NTFS.

  • Linc Davis Level 10 (192,275 points)

    In the Finder, press the key combination shift-command-C, or select

    Go ▹ Computer

    from the menu bar. A window will open showing all mounted volumes. Select the one in question and open the Info window. What is shown as the Format in the General section?

  • MrsWeir Level 1 (0 points)

    it is set up as a NTFS. not sure why it worked before. and now problems. Can I reformat the drive or download something to use it with?

  • Tlix Level 4 (1,420 points)

    Yes you can format it using Disk Utility. To either Mac OS Extended format or MS-DOS FAT format. Mac format will only work on Macs whereas the FAT format works on both Windows/Mac. Doing so will erase the data from the hard drive though.


    Open up Disk Utlity from the Utilities folder which is in the Applications folder. Select the hard drive on the left hand side and go into the Erase tab. From there change to the appropriate format and click erase.