I can't find anything that simply answers this question: Same external drive as I've had for four years. Formatted NTFS and removed all original software. Suddenly windows says must reformat, but is unable to reformat. Connected with USB, as always, connected to several machines with several diferent OS's. I would reformat and run data recovery, but I am unable to do so, apparently. I've had externals go out on me before, but they all claimed i/o error. This is not the case here. This is the whole story. There are no relevant variables. How do I fix, or do I pay a data recovery company to get my disk info? Thx.