While the solution typically involves disabling Windows security features to allow the unsigned driver to load, doing so exposes the system to significant security vulnerabilities. For professional manufacturing environments, the only stable resolution is obtaining a legitimate license, which replaces the complex virtual emulation with a stable, supported licensing service.

Find and the entry named UpperFilters if it exists, then restart. Bypass Driver Signature Enforcement:

Group Policy can be configured to stop Windows from automatically updating your USB controller drivers.

Reboot your PC and reinstall the updated MultiKey.sys driver. 4. Remove Conflicting USB Devices

: Unplug other USB peripherals (like 3D mice or cell phones) before starting Mastercam to rule out driver interference.

If you upgraded from Mastercam X7 up toward Mastercam 2022, conflicting registry keys might point the virtual USB bus to the wrong directory. Press Win + R , type regedit , and hit Enter.

: If you are using a legitimate license and HASP key, Mastercam provides a System Inspector Utility

When you see a , it means the Mastercam application tried to "shake hands" with the fake dongle driver, but the driver was missing, corrupted, unsigned, or blocked by Windows.

Windows Security features like "Core Isolation" can block unverified or older virtual drivers from loading.

To understand the error, you have to understand the lock.

Navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 . On the right side, find and the UpperFilters entry. Restart the system. 3. Reinstall HASP Drivers