Navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36fc9e60-c465-11cf-8056-444553540000 In the right pane, look for or LowerFilters . Right-click and Delete them. Restart your PC. ⚡ Quick Troubleshooting Tips
| Cause | Explanation | |-------|-------------| | (Windows 10/11) | The virtual driver is unsigned or uses a test signature. Modern Windows blocks it. | | Windows Update | A Windows update may break the virtual driver or re-enforce driver signing. | | Corrupted driver installation | Incomplete emulator setup or leftover registry entries. | | Antivirus interference | Antivirus deletes or quarantines key emulator driver files (e.g., multikey.sys , vusbbus.sys ). | | Outdated emulator | Emulator designed for older Mastercam versions fails on newer Windows builds. | Mastercam X7-2022 Virtual Usb Bus Error 39
The following procedures are listed in order of least invasive to most comprehensive. ⚡ Quick Troubleshooting Tips | Cause | Explanation
If you use both a physical USB dongle (NetHASP) and a virtual license, they conflict. | | Corrupted driver installation | Incomplete emulator
Navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36fc9e60-c465-11cf-8056-444553540000 In the right pane, look for or LowerFilters . Right-click and Delete them. Restart your PC. ⚡ Quick Troubleshooting Tips
| Cause | Explanation | |-------|-------------| | (Windows 10/11) | The virtual driver is unsigned or uses a test signature. Modern Windows blocks it. | | Windows Update | A Windows update may break the virtual driver or re-enforce driver signing. | | Corrupted driver installation | Incomplete emulator setup or leftover registry entries. | | Antivirus interference | Antivirus deletes or quarantines key emulator driver files (e.g., multikey.sys , vusbbus.sys ). | | Outdated emulator | Emulator designed for older Mastercam versions fails on newer Windows builds. |
The following procedures are listed in order of least invasive to most comprehensive.
If you use both a physical USB dongle (NetHASP) and a virtual license, they conflict.