Hello,
1.
Try using the commands in the command prompt to specify the allocation unit size. Please refer to this link: https://learn.microsoft.com/en-us/windows-server/storage/file-server/ntfs-overview
2.
It is possible that the hidden file you are seeing on your USB device after formatting is a system file that Windows creates during the formatting process. This file is used to store information about the file system and is necessary for the proper functioning of the device.
Best Regards,
Hania Lian
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