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.
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. usb-write-protect
If the drive isn't physically broken, you can usually clear the protection with these steps: This is the most reliable software fix for Windows users. Modern flash drives have a built-in "retirement plan
There are three main reasons a drive enters this "read-only" state: usb-write-protect