Modern flash drives have a built-in "retirement plan." When the NAND flash memory cells wear out or the controller detects a hardware failure, it often switches to a permanent read-only mode. This is a safety feature to let you save your data before the drive dies completely.
There are three main reasons a drive enters this "read-only" state: usb-write-protect
Some older or high-security drives (like certain SanDisk models) have a tiny physical toggle on the side. If it’s flipped, the drive won't let you write anything. Modern flash drives have a built-in "retirement plan