I just installed a new 1TB Toshiba external hard drive in my laptop (Windows 7) and was in the middle of creating partition (250GB each) when I was asked to format it. I choose NFTS when formatting but each partition cant be formatted, there's always these pop up message said that windows is unable to complete the format, the cluster size is too big to be formatted, etc. I don't know when it's happened but when I checked again the portable hard drive was not detected in 'My Computer'. However, it was only appear in Storage - Disk Management but I still cant format it. Before creating the partition there was some file/system file that originally was inside the hard drive (set up.exe, folder NTI Backup and folder formatting for Macs, etc) and now it was all gone. How do I resolve this? Thanks
Windows often fails to assign a drive letter to external hard drive, and without a drive letter, the drive isn't going to be visible in Windows.
Therefore, try to assign a letter to this drive: http://technet.microsoft.com/en-gb/library/cc757491%28v...
This way worked on my hard drive last time. I hope it will work well on your drive.