OSX and Windows 10 backup Drive

if you want to use Time Machine you will need to use a drive formatted to Mac Extended (Journaled), if you want to back up Windows you should use an NTFS formatted drive to keep the Windows permissions intact. If you plan to do this on one drive and one partition goes bad you could loose both sets of data. I would recommend two drives, one for each OS. Brand doesn't matter, I use Seagate, I've had issues with Western Digital, but others here have had issues with Seagate and no problems with Western Digital.