I have (1) 640gb, (2) 500gb wd passport and had no problem with them. just bought a 1tb and it keeps giving me a "can't eject because device is in use" while i'm transferring files from one to another, then finally the 1tb will just eject itself???????...all the hard drives are formatted the same...exfat. any help???? Error: "WD My Passport 0740 Media is in use and can't be powered off." it says this about ten times then dismounts with this code: "The operation cant be completed because one or more required items cant be found. (Error code -43)".