My computer is windows 7 operating system if it matters, I have (4) 1 tb hard drives and they are working perfectly fine. I have put many files on each one of these hard drives when I click my computer it shows the c drive and then all of the other drives as well but the drives show up in my computer as 931gb free of 931gb free, I click the hard drives and the files are there and work fine it just isn't showing disk space used.