There are many terabyte FAKE drives out there. The symptom is as you wrote above. How sure are you that:
1. It really is a 2TB Flash drive?
2. Is it formatted NTFS?
3. How much were they?
Why question three is that the price is usually the dead giveaway that it's fake.
More at https://www.google.com/search?q=fake+2tb+flash+drive
I found some inexpensive 2T flash drives, thought I'd use them to back up my music and video. When I try to copy files to the flash drive, only some of the files get copied. Some folders are empty, some are complete. If I copy again to the folder, I can watch it copy, can see the files in the new folder, but if I close the folder and reopen it, the files are gone.I've tried the scan/repair option, it says it finds errors, fixes them, didn't help. Tried reformatting, didn't help. 4 out of 4 drives have the problem. It's not the files because I can successfully copy them to my hard drive and/or to smaller capacity flash drives. At one point I copied a music file, played it from the drive, then closed and opened the folder and it was gone. Also want to add that I'm not very computer literate. Is it simply that i bought some crappy flash drives or is it something I'm doing wrong?