Once installed, "Virtual USB MultiKey" should appear under "System devices" in the Windows Device Manager . Common Issues & Troubleshooting
Situation: After Windows cumulative update, Mastercam reported “No valid multikey found” on 6/1/2025 across 3 stations. Action: Reinstalled Multikey driver with vendor-signed installer, moved dongles from USB 3.0 front ports to USB 2.0 rear ports, and blocked the problematic update via Windows Update for the fleet. Result: All stations restored within 2 hours; added update-block rule and driver reinstall procedure to SOP.