I have a new laptop with Windows 10. I put my old laptop hard drive in an enclosure and Win10 promptly trashed its file system. I'm still trying to work through that issue, but I'm afraid it did something else to my friend's external drive, too. He has a 2TB WD Passport. We plugged it in to my laptop and it was working fine but after I gave it back, he plugged it into his Win7 system and it took like 10 minutes to show up (Windows detected it, but explorer just sat there spinning for 10 min, also he opened Disk Management and that program locked up too, until the disk showed up). Once it showed up it seemed fine, but if he clicks a folder it takes a long time to show up, and if he tries to open a file it takes a very long time to open. He's going to back everything up and reformat the hard drive, that's how bad it is.
It was working fine before, so it had to have been my computer that caused the problem. But I have no idea what could have happened, I've never seen anything like that. Now I'm afraid to plug any external drives into my computer because it seems like it's doing something weird to them. I don't see how it could be a virus or anything like that. I've only had the computer for about 2 weeks (and I have antivirus). Has anyone seen this before? Anything I can try? I think it may take several days for him to back all his files up because the hard drive is so sluggish.