Previous 1 2 Next 16 Replies Latest reply: Oct 17, 2015 9:07 AM by Kurt Lang
macjsus Level 1 (0 points)

I heard somewhere that if a External Hard Drive is formated exFat on a Mac, it wont work on Windows, unless it is Mac OS X 10.7 (Lion) or 10.8 (Mountain Lion). I have Snow Leopard (10.6.8) and I wanted to know if I format my External HD for exFat will it work on Windows? I currently have is formatted as Fat32 but there is a 4GB limit so I wanted to try exFat.

MacBook Pro, Mac OS X (10.6.8)
  • mende1 Level 10 (92,156 points)

    exFAT works on Windows (XP, Vista, 7 and 8) and OS X (10.6.5 and newer), so it should work without any problem. If you format it on OS X, a Windows PC should be able to write on it without any problem.


    Note that, before erasing the external disk, you have to copy the files onto the internal disk, so you won't lose the files

  • steve359 Level 6 (13,297 points)

    It did not work for me formatted on OSX (I have 10.6.8) and had to use the Windows format.  Someone dug up a technical fact about Mac using a blocksize Windows does not like but windows uses a blocksize OSX can handle.


    But your mileage may vary.

  • mende1 Level 10 (92,156 points)

    I have seen different cases, but I think you are right on most of the cases. You have to format the external disk on Windows to make sure it will work on OS X and Windows

  • Kurt Lang Level 8 (36,645 points)

    It's a known issue that, depending on how big the drive is, formatting exFAT in OS X uses too large of block (cluster) size that Windows doesn't like. Format the drive from within Windows with a block size no larger than 1024 and you should be able to use the drive on both platforms.

  • Doghair Level 1 (0 points)

    I recently formatted a 16GB drive on Mountain Lion as exFAT.

    It was NOT readable by a Windows XP machine, but was happily readable on a Windows 7 machine (or was it Windows 8? Not sure).

    No idea of Vista's behaviour.

  • Kurt Lang Level 8 (36,645 points)

    For any and all reading this topic, it should be made known that MS very recently dropped all further development of exFAT. It was never finished as it was (a final specification was never released).


    If you need to share a drive between platforms, then the best supported options are:


    1) Format the shared drive as NTFS and install Paragon NTFS on your Mac.


    2) Format the shared drive as HFS+ (Mac OS Extended) and install HFS+ in Windows.


    I have tried the first, and it works very well. There's also Tuxera NTFS for Mac, but Paragon's software is cheaper and does the same thing. Can't comment on how well the Windows software for Mac formatted drives work.

  • careyau Level 1 (0 points)

    Kurt, what is your reference for saying that MS has dropped development for exFAT? I have been searching Google for a refrence to this and I cannot find anything.

  • ds store Level 7 (30,325 points)

    Doghair wrote:


    I recently formatted a 16GB drive on Mountain Lion as exFAT.

    It was NOT readable by a Windows XP machine, but was happily readable on a Windows 7 machine (or was it Windows 8? Not sure).

    No idea of Vista's behavior.



    exFAT has to be formatted on the Windows machine and XP needs exFAT installed as a free download from Microsoft.




    Don't buy the F.U.D.


    There would be  tanks in Redmond if Microsoft even attempted to discontinue support for a  drive format they released.


    With NTFS one just has to keep paying over and over as Microsoft makes changes to it for licence fees they collect from companies using it.


    A truely open drive format is needed, but with two corporations playing games for profit by controling hardware and software it's kind of hard to implement.



    Why Apple formats exFAT in a manner that can't be easily read by Windows remains a mystery.

  • Kurt Lang Level 8 (36,645 points)

    Kurt, what is your reference for saying that MS has dropped development for exFAT?

    It was another member of these forums. Normally very accurate in their statements, so I assumed them to be correct. I looked again myself and found out this is not the case. At least, not exactly.


    What MS did was make a change in Windows 8 so that you cannot format an internal drive as exFAT. You can still format any type of external drive that way (hard drive, USB drives). The whole purpose of exFAT was to allow easy transfer of large files between platforms in a format that didn't require third party drivers on either the Mac or Windows to read the drive.


    To make sense of why MS would cut off the use of exFAT for internal hard drives, it has to be understood that exFAT still doesn't have a final specification. In other words, it's still a work in progress. So Microsoft's thinking is probably something like this; "Don't use exFAT on an internal drive. Use NTFS, which is known to be stable and reliable. It's okay to use exFAT on external drives since you can get the original data again from an NTFS drive if the external exFAT drive is having trouble."

  • Oviyafrom北京 Level 1 (0 points)

    Hi Kurt,


    I'm using Mac MINI for years. Recently i bought a 1 TB Mac mini last month. As usual, I partitioned the Hard drive in to Macintosh (250 GB) and ABC (750 GB). Last week i was move files of more than 4 GB so i  decided to format a USB using ex-fat. Unfortunately both my USB and my partitioned hard drive ABC (750 GB) had same names. I mistakenly formatted the partitioned hard drive using ex-fat, ending in all the data erased as well cannot find the partitioned hard drive  on My finders. Only Macintosh (250 GB) is visible.


    My question is


    1. how to bring back my partitioned hard drive ABC (750 GB)?

    2. is it possible to retrieve the lost data?

  • Kurt Lang Level 8 (36,645 points)

    Ouch! It's odd that the mistakenly formatted drive won't show on the desktop. An exFAT drive should still be visible.


    This won't be easy. Typical Windows recovery software depends on the file table to determine what files are on the drive and where to recover them from. Formatting the drive wiped out the file table. But this was a Mac formatted partition to begin with.


    You can give FileSalvage a try. It will run as a working demo and allow you to recover a few files to see if it works. I recommend this one in particular because it has an option called Salvage All Files, which will attempt to recover data from a drive that won't mount on the desktop.


    This is a very long process, especially on such a large drive/partition. It works by examining the entire drive for BOF (beginning of file) markers, and then recovering whatever it can.


    Do not write anything to the drive you need to recover data from. If you know there's more data on the ABC drive to recover than will fit on the 250 GB partition, then you'll need an external drive large enough to hold the recovered data. You can't save it back to the same drive you're recovering data from. One, the software won't let you. And two, that's because writing recovered data to the drive could destroy other data that hasn't been recovered yet.

  • Oviyafrom北京 Level 1 (0 points)





    Screen Shot 2015-10-17 at 18.06.46.png


    ABC Drive still not visible. Don't know what went wrong. I haven't tried with File Salvage yet. Confused to proceed further.


    Thanks for your advance help

  • macjsus Level 1 (0 points)

    Once a flash drive disappeared on me, it got corrupted. I would check to see if it works a on windows machine, if not then it is corrupted you may need to take to a data recovery service.  If it does show up then reformat it on Windows.


    The only other option I can think of is to run disk utility via the terminal and see if it will list the disk there.


    Here is some info on using the command diskutil in the terminal: t-1

  • Kurt Lang Level 8 (36,645 points)

    Untitled is the default name given to a new partition. An erase normally maintains the current name. So just on the surface, it appears the ABC portion of the drive was somehow incorrectly repartitioned.


    No doubt something is wrong when the bar graph shows two partition names, but the column view on the left only shows one. Try the FileSalvage demo and see if it recognizes the unmounted drive under the Salvage All Files option. That will at least tell you if the data can be accessed.

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