A:AnswerIt’s a decimal 4TB while you computer represents it in binary. Base 10 vs base 2.
4*1000*1000*1000*1000 = 4,000,000,000,000/1024/1024/1024/1024 = 3.637 TiB
http://knowledge.seagate.com/articles/en_US/FAQ/172191en
A:AnswerMyCloud drive failed after 5 years so I didn't want to go through the installations and hassles of MyCloud, so I bought the plain "WD bacjkup drive". If you have USB port open this drive will not disappoint you.