In Device Manager, find the device with the yellow exclamation mark (Error 39), right-click, and select Uninstall device .
Editing the registry incorrectly can damage your Windows installation. Follow these steps carefully.
Simply reinstalling Mastercam or its drivers often fails because remnants of previous driver installations remain in the system. These leftover files can conflict with new installations, causing persistent Code 39 errors even after multiple reinstall attempts.
Look for entries with a yellow warning triangle, such as , Sentinel HASP , or SafeNet USB Key .
Error 39 is a standard Windows Device Manager error code that translates to: "Windows cannot load the device driver for this hardware. The driver may be corrupted or missing." mastercam x72022 virtual usb bus error 39 fix
Modern versions of Windows 10 and 11 include a security feature called (part of Core Isolation). This feature prevents unauthorized code from running in high-security processes but frequently blocks older virtual drivers used by Mastercam emulators. Experts from Matsusada Precision and RT Systems identify this as the leading cause of Code 39 errors for USB-related hardware. How to Fix: Open Windows Security and navigate to Device Security . Click on Core isolation details . Toggle Memory integrity to Off . Restart your computer to apply changes. Secondary Cause: Corrupted Registry Filters
Locate the specific class GUID corresponding to your USB driver (commonly 36fc9e60-c465-11cf-8056-444553540000 for USB devices).
This specific error with Mastercam is almost always caused by a conflict between the older driver files installed by the Mastercam setup (specifically the Sentinel/HASP driver) and a newer version of Windows (Windows 10 or 11), or a corrupted registry key regarding the USB filter driver.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceGuard\Scenarios\HypervisorEnforcedCodeIntegrity Microsoft Learn 4. Reinstall Virtual USB Drivers In Device Manager, find the device with the
Mastercam X7 2022 is a popular computer-aided manufacturing (CAM) software used by machinists and manufacturers worldwide. However, some users have reported encountering a frustrating error known as the "Virtual USB Bus Error 39" when attempting to run the software. In this article, we'll delve into the causes of this error and provide a step-by-step guide on how to fix it.
Legacy emulators for older Mastercam versions (like X7) lack modern digital signatures. You must force Windows to accept these drivers.
Press 7 or F7 to choose . Summary Table: Troubleshooting Steps Potential Outcome Disable Memory Integrity Resolves driver loading blocks from Windows 11. Delete Registry Filters Cleans up corrupt USB registry entries. Reinstall Aladdin Drivers Fixes damaged driver files. Disable Driver Signature Permits unlicensed virtual drivers to load.
Ensure you are using the latest HASP HL driver compatible with your specific Windows version. Simply reinstalling Mastercam or its drivers often fails
Modern versions of Windows include a security feature called Memory Integrity (part of Core Isolation) that blocks unsigned or vulnerable drivers from loading into the system memory. This feature frequently triggers Error 39 on virtual USB bus drivers. Open the , type Device Security , and press Enter . Click on Core isolation details . Locate the Memory integrity toggle switch. Turn the switch to the Off position. Restart your computer to apply the security changes. Step 2: Disable Driver Signature Enforcement
The "Code 39" error in Windows Device Manager specifically indicates that the system cannot load the required device driver. However, for Mastercam users, the full error message often contains an additional critical line: "Windows cannot verify the digital signature for this file. The signing certificate for this file has been revoked" .
: Reboot your computer to apply the changes. The driver should now load without Error 39. Secondary Fix: Windows Registry (HVCI Disable)
Thales releases updates quarterly. Do not rely on old Mastercam installers.