If you are getting a specific error (like Code 39), you may need to "fix" the driver files: Remove existing drivers : Go to your MultiKey folder and run the remove.cmd remove.bat file as administrator. Replace files : Some users find success by replacing the original multikey.sys with a version specifically patched for 64-bit systems. install.cmd as administrator. When prompted by Windows Security, select Install this driver software anyway Troubleshooting Tips Problem with virtual multikey - Microsoft Q&A
Upon reboot, press to select Disable driver signature enforcement . Enable Test Mode : Open the Command Prompt as an Administrator. Run the command: bcdedit /set testsigning on . multikey.sys windows 11
Before proceeding, ensure that multikey.sys is not required for a legitimate piece of hardware you actively use (e.g., an expensive macro keyboard from 2015). If it is, check the manufacturer's website for a Windows 11 signed driver update. If no update exists, you must choose between the hardware and the OS. If you are getting a specific error (like