If you are short on time, run through this rapid-fire checklist:
: Windows Explorer actively displaying the drive's contents or a background process accessing a file on the USB. rufus access to device denied windows 7
Open Task Manager ( Ctrl + Shift + Esc ) → End explorer.exe . Don't worry – you can restart it later via File → New Task → explorer.exe . If you are short on time, run through
Ensure you're using the latest version of Rufus. Sometimes, updates include fixes for such issues. Ensure you're using the latest version of Rufus
If all else fails, it might be time to consider an alternative to Rufus. Several other excellent tools can create bootable USB drives on Windows 7:
A conflict in the Windows 7 mount manager can occasionally tie up device access permissions. Changing the drive letter forces Windows to reassign access permissions.