Portable hard drive

[dverdier]

I have a 4tb drive that somehow lost connection during a multi file transfer. It's effectively ready only on that pc. The box is blacked out and not checked. I've read this doesn't mean read only but that's why I say effectively, because that's how it acts. I've tried chkdsk and a few other things. Even seagate's own software. One strange thing is that it operates totally normal on my laptop. I have no idea how to find out which file it was one when it lost connection. No idea how to repair once I'm able to find the bad sectors. I've spent many hours with google and you tube to no avail. I've seen guys recover data from worse cases. There has to be a way without formatting the disk. I don't want to loose everything on it and I  would like to finish filling it up to make more room on that pc. Please if there is someone out there that knows exactly what to do, I'd appreciate your instruction.