As Mrs. R said, you get that message usually on a flash drive if it has bad sectors that would prevent it from accessing (usually the FAT table won't associate with the data any more). You can take the following steps:
1. Try a different USB port, or even better a different port on another PC. It could be just a bad read.
2. You could drop to a admin DOS command prompt and try CHKDSK /f to attempt to fix the bad sectors. WARNING: if there is any data on the sectors it thinks are bad, it'll typically copy those file sections into unusable files. So, you might get all, some, or none of your data back in this case. Only recommended if you're really desperate or really know what you're doing.
3. Use a file recovery software. Here are one's I've used in the past:
Teracopy for Windows - this one will copy files it can reach, but I don't think it'll work on a disk that can't be accessed. It's more for "This file is fighting back" sort of scenarios.
Roadkil's Unstoppable Copy - this is a great little program that does exactly what you would need for free, but it's older than dirt and I haven't tried it on Windows 10 boxes. Worth a shot, though.
Puran File Recovery - I've not used this one much as the previous two, and it's a little old as well, but if memory serves it's not bad either. There is a newer version than the one listed, but it's pay for use.
Let me know if any of this works - There are other options out there that I haven't personally tried (there's a good list
here if you want to dig yourself).
Good Luck!