You’ve got three options to add write support: Tuxera NTFS for Mac, Paragon NTFS for Mac 14, and NTFS-3G. Screw ExFAT, and HFS+ is right out, leaving you with NTFS, which is read-only by default in macOS. But luckily, there’s actually competition in this space these days. So you want good performance accessing those drives, you don’t want to lose all your data if a fly lands in the wrong spot in Belize, and you need read/write access from Mac as well as Windows? Sucks to be you. You’re probably not like me, but if you are, you probably don’t want to be using ExFAT on all of those disks, because ExFAT sucks. If you’re like me, you use Macs and PCs on the same desk, have a pile of external disks ranging from 1-2 terabytes to a bunch of terabytes, and you’ve got a bunch of crap on all of them that needs to move around a lot. Update! I revisited this question with a modern computer and a slightly different outcome.