So I partitioned one of my external HDD's for my bootcamp windows, just so I could install some Windows files without having to resize my partition by erasing it and reinstalling. Using disk utility on the Mac side, I partitioned it to be half Mac OS Extended (Journaled) and the other half ExFAT.

Both drives show perfectly well on my Mac, but when I boot in windows, it only shows my read-only Mac OS Extended partition and when I open the partition display in windows, it says that there is only one partition (unknown) and it is all unallocated.

Also, it already has files on the mac side so I don't really want to reformat if possible.

-- Macbook Pro Late 2013 13" Intel i5 256GB

2 Answers 2


From the Tom's Hardware Forum:

By default, the OSX disk utility creates a new partition as GUID. Windows can't read it. You need to create the partition type as MBR, which Windows can read. Then format as exFAT and both machines will read it.


I had the same problem, I created an exFat partition vía disk utility in OSX along with 2 other partitions (one for Time Machine to make OSX backups and other for bootcamp recovery backup of Win7 using a third party program). When I enter windows vía bootcamp, I couldn't see the the exFat partition. I just entered the disk management of Win7 and change the drive letter of the exFat partition. It seemed it was in use by another network device so that worked for me.

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