If the basic fixes do not work, use these methods to force Windows 7 to relinquish control of the device:
Do not run Rufus with the ISO file stored on the same USB drive you are trying to format. This creates a recursive lock that triggers an access denied error. Advanced Troubleshooting Steps rufus access to device denied windows 7
Applications like Windows Explorer , antivirus scanners, or cloud backup services may be "holding" the drive. Close all open folders and temporarily disable active antivirus protection before clicking "Start" in Rufus. If the basic fixes do not work, use
Rufus includes "cheat modes" to bypass specific locking issues: rufus access to device denied windows 7