Formatting flash drive on MAC so it can be used also on Windows

Discussion in 'Mac Basics and Help' started by Colcho, Nov 11, 2009.

  1. Colcho macrumors newbie

    Nov 11, 2009

    I'm trying to format a usb drive on MAC OS, but want windows machines to be able to view and use it. From this forum and few other places, I've read that all I have to do is use Disk Utility and select MS-DOS(FAT) in the "Volume Format" drop down menu. I also wanted to erase all data from the USB so I marked "Zero Out" data in the security options.

    Formatting was completed successful(no errors/warnings). On my MAC I can see the usb mounted and empty in the finder. When I plug the same usb to a windows, the os tells me that the drive must be formatted. In the windows format program, the first drop down menu has only 200MB option. My usb is a 16GB Corsair, so 200MB is no where near the truth.

    I'm using iMAC with os 10.5.8 and tried the USB on my Vista boot camp partition, on a virtual windows 7 and on a completely different pc -> windows XP(actually the virtual win7 didn't even detect the drive).

    Don't know if it matters, but before the formatting, I had 10.4.11 installed on the usb drive.

    Any suggestions on how to make this usb usable by Windows and Mac OS?

    Thanks in advance,
  2. belvdr macrumors 603

    Aug 15, 2005
  3. Colcho thread starter macrumors newbie

    Nov 11, 2009
    I already managed to brake one usb drive in a similar way, so I'm not up to experiments :)

    Do you think that the 200MB setting for the drive size will not brake it or at least make only 200MB usable? Maybe once it is windows formatted, the second time I try to format it - some more reasonable size will be available in the drop down menu, but as noted I prefer someone to confirm that formatting it in 200MB will not brake the usb drive.
  4. belvdr macrumors 603

    Aug 15, 2005
    I have never had a USB drive break due to formatting.

    Go to the Mac and delete all the partitions on it using Disk Utility. Then take it back to the Windows machine and get it formatted.
  5. wrldwzrd89 macrumors G5


    Jun 6, 2003
    Solon, OH
    This can be done on Mac OS X - you need to set the partition scheme to MBR, if it isn't already, for Windows to recognize it. This is done from Disk Utility. After selecting the disk, go to the Partition tab (if there is no Partition tab, you've selected the wrong thing). You want to click Options... but it's grayed out. To fix this, click the pulldown that says Current. Change it to 1 Partition. Then, you can click Options and set the partition scheme. Then, once that's done, select MS-DOS (FAT) as the partition format. Let DU do its thing.
  6. Colcho thread starter macrumors newbie

    Nov 11, 2009
    Thanks very much, this worked just fine.

    It looks like I had the usb set to "Mac OS Extended (Journaled)" and I only formatted the partition to FAT. Now the usb itself is marked as FAT.

    After some(a lot) experiments with formatting on MAC, when the usb was plugged it was mounted, but whenever I tried to access it an error appears and was automatically unmounted. Support told me its broken and took it :)
  7. queshy macrumors 68040


    Apr 2, 2005
    Don't mean to bump an old thread but THANKS A LOT! That worked perfectly.

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