mike s, you are right of course. Thank you so much.

MIKE S, thanks for reminding me, I did miss H2testw
Anyway, I checked on one of the flash drives with H2testw (recommended) and it said that "The media is likely to be defective" , in addition there...

Sorry to say the none of the solutions worked for me.
As far as I read on the net, Windows 10 does not support a flash drive this size 1TR.
Microsoft suggests "
you can try EaseUS partition tool
...

Thanks Spunk for the detailed answer.
I do mean 1TB USB Flash Drive.
In the first place , the Flash Drive was formated as exFAT and yet, as I tried to copy some more files - some of the already...

I am trying to store large files , of course.
When you say "Fat will work just fine" you mean Fat32, right?
I am at a stage where I would like the DOK to work one way or another.
How can I format...

thank you.
If I try (as I did in the previous DOK) to format I get no option as Fat32. The alternative is NTFS.
Besides, Files larger than 4GB can NOT be stored on a FAT32 volume.

Hi,
I just bought a disk on key (DOK) 1TR. The device file system is exFAT.
When I try to copy files (movies for example) it copies as looks like OK.
Some of the files work (from the DOK), some...