Currently using a windows 10 laptop. Today bought a new Seagate Backup Ultra Touch 2 TB Hard Drive. As I saw it comes with default exFAT format. I format to NTFS suddenly. I am also planning to buy a macbook pro this holiday season. I get to know that NTFS can only be read in mac not write. So the only option is to make my hard disk exFAT again. But the thing is what allocation size I should set? The default windows 10 is showing 512k. I don't remember what was the factory set allocation size when it came out of the box from seagate. Please help me out! Also I think allocation size of 512 will be too much, how about 128k?