The USB stick is a hardware component which is used to store data. It has a switch which slides up and down to enable or disable the write protection lock. Confirm that the switch is not disabled from the write mode. If it is locked, then unlock it and resume writing. Ascertain that the directory written into is not read-only. If it is read-protected, then right-click on the folder and uncheck the "Read Only" button. There are many online recovery tools which are related to a specific brand of USB stick. For example, utilise the JetFlash Online Recovery tool to repair Transcend USB keys which gives the user the flexibility to either maintain stored information or the format key. Lastly, formatting the USB key is the final solution.