8 Replies Latest reply: Jan 7, 2007 1:03 PM by poisongirl
Lord Neslon Level 1 Level 1 (0 points)
I have just got a Mac and want to user the external hard drive that was previously used by my PC. I do not have read/write permission to the external hard drive - I guess because it is formatted for NTFS. Do I need to reformat the external drive to allow my Mac to be the primary user of it with full access?

I have copied all the data off the external drive in anticipation so assume that I need to reformat it from my Mac and then copy the data back? Is that right or is there anehotr way? If re-format is the way to go what tool do I use - Disk Utility?

Thanks in advance.

MacBook, Mac OS X (10.4.8), 2GB Ram
  • JoeyR Level 6 Level 6 (8,275 points)
    Yep... You answered your own question

    OS X can read from NTFS formatted drives, but it cannot write to them. You can use Disk Utility to reformat the drive. The most common format to use (if PC compatibility is not an issue) is Mac OS Extended (Journaled)). If you want to use the drive on both Macs and PCs, you can select the MS DOS format option. That will format the drive in FAT32 so you can use it on both Macs and Windows machines.
  • Craigy-Baby Level 1 Level 1 (15 points)
    JoeyR is completely right, but something that is also worth noting is that, if you format your drive to use FAT32, you won't be able to copy any single file onto it that is larger than 2GB.

    I have been bitten by this problem several times. There doesn't seem to be a format that both Windows and OS X can both completely use. Apple don't fully support NTFS, Microsoft don't support HFS at all, and FAT32 blows.

    Yeah, thanks guys...
  • JoeyR Level 6 Level 6 (8,275 points)
    FAT16 has a max file size of 2GB... FAT32 has a max of 4GB (still a limit... especially if you plan to work with video files, but most single files will never be this large). This is a good site to get the details on the limitations of the MS filesystems:


    Ideally, if you're just going to use it with your Mac, using a Mac format is the way to go.
  • Craigy-Baby Level 1 Level 1 (15 points)
    Ah... 4GB instead of 2GB, you say? I stand corrected. Its not as bad, but its still too small for, say, a DVD image.
  • Lord Neslon Level 1 Level 1 (0 points)
    Thanks very much for the advice and clarification. You answered the qeuastions that I would have followed with about the differences and drawbacks of the different file systems.

    I use my Mac a lot for video so file size is very important. I hope ony to use my PC as a print server so don't expect that it will need space on the exrernal hard drive.

    Thanks heaps.
  • Dom_Harrington Level 1 Level 1 (120 points)
    I have an 80GB external and have created 2 partitions on it, one for a 60GB HD backup and then the remaining space (about 15GB) for a FAT32 partition for use whenever I may be on windows machines, like school for example.....
  • Lord Neslon Level 1 Level 1 (0 points)
    Thanks fo the tip. I actually considered that as an option but have decided to go all Mac.

  • poisongirl Level 1 Level 1 (100 points)
    A DVD image will be no larger than 4.7GB as that is the size of the DVD. It is possible to have DVD images that are less than that, as it just goes by how much data was actually on the DVD. So I would just look at the file size (or total if more than 1 file, but I am assuming you are speaking of an actual Image file like the ISO format etc) and see if it is possible or not.