How to use a PC-formatted drive on the Mac

[iMore.com]

Macs can easily read PC-formatted hard disk drives. Writing to them, however, is a different story.
If you've switched to the Mac, welcome aboard. Your old external Windows PC drive will work great on the Mac. Apple has built OS X Yosemite and some previous OS X releases with the ability to read from those disks just fine. If you're using such a drive and you'd like to write new data to them, you'll find you can't unless you add new software. Fortunately, you don't have to spend a dime.

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