May be check the partition type you are using if you are using FAT 16 then you cannot copy more than 2 GB
FAT16 has a maximum file size of 2GB, and despite the much larger hard disk size supported by FAT32, the maximum file size only doubled to 4GB.
This may be a situation where the flash drive is faulty or “hacked” to show more capacity than it actually has available. Look at this external forum posting on what one user did to repair their “hacked” USB flash drive. Note that the tips/tricks it recommends are not for the faint of heart or new computer users. I did use a similar process though on a USB drive I received. It had some demo security software on it that I was unable to remove by any other method. It cleaned the drive right up and I was able to use the full capacity.
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