I need to share files between Windows and Mac, so I chose exFAT as the file system for my external hard drive.

But soon I found a serious problem, when I put too many files (like 5M) in the hard drive, OS X can't mount it. Then I have to delete them in the Windows machine, after that it works well in Mac. Does anybody know how to solve the issue?

  • Have you tried repairing the disk (both on Mac and Windows)? – At0mic Sep 27 '15 at 16:19
  • Yes, but Mac still can not mount it. – Dingbao Xie Sep 28 '15 at 13:46
  • "5M" as in 5MB of files or 5 MILLION files? If the latter you may have run into a file system limitation of the number of files a Mac can read on an exFAT volume (just a guess). Try putting the files in one or more folders. Then if it can see the folder(s) but not the files in the folders then my guess is correct. – Steve Chambers Sep 29 '15 at 15:34
  • 5 million files. – Dingbao Xie Oct 1 '15 at 11:26

The OSX EI Capitan solves the problem, apple fixes it in the new OS.


In case you run into any further issues while using El Capitan and need different access between Windows/Mac file systems, you might give some 3rd-party software a try. I've had great luck with the free open-source version of Tuxera NTFS-3G

  • Thanks for your suggestion. If it does not slow down the read/write speed too much, I'll give a try. – Dingbao Xie Oct 11 '15 at 5:44

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