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What is the file system for external hard disk that supports access from Windows and Mac OS X? Also, I would like to backup using Mac Time Machine application, and use the disk to store other data.

I'm currently using Seagata Backup Plus Portable as the external hard disk. Windows OS: Windows 10 Mac OS: OS X El Capitan

marked as duplicate by DavidPostill, karel, Steven, nc4pk, mdpc Mar 1 '16 at 0:35

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For a hard drive to be able to be read and written to in both a PC and Mac computer, it must be formatted to exFAT or FAT32 file format. FAT32 has several limitations, including a 4 GB per-file limit. This is a file system limitation that affects both Mac's and PC's, and the only workaround is to format the drive to exFAT.


The Disk Utility advanced options of El Capitan are hidden and you needed, first:

  • Quit Disk Utility.

  • Open the Terminal utility.

  • Run the following Command:

           defaults write advanced-image-options 1
  • Relaunch Disk Utility

And now, just format your USB with MBR Partition (Master boot record) and exFAT file System. The USB now can mount in OSX & Windows.

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