Click -> Scan for hardware changes to force reinstall. Summary Checklist Disabled Core Isolation? Yes/No Cleared Registry Filters? Yes/No Updated HASP Driver? Yes/No
Below is an in-depth guide on why this happens and how to resolve it. Understanding Error Code 39
. This error indicates that Windows cannot load the device driver because it is either corrupted or missing. Primary Cause: Core Isolation (Memory Integrity)
Go back to Device Manager and check if the Virtual USB Bus warning icon has cleared. Method 5: Update the Virtual Bus Driver Software Manuallly
typically occurs when the Windows operating system cannot load the device driver for the hardware, often due to security features or corrupted registry entries . This error affects Mastercam versions from X7 through 2022, primarily on Windows 10 and 11, where advanced security settings may block older virtual drivers. Primary Causes Mastercam X7-2022 Virtual Usb Bus Error 39 - Google Groups Mastercam X7-2022 Virtual Usb Bus Error 39
If this command returns a directory name, you must delete it. If the folder is in use, you may need to use a tool like or Dism++ to launch a TrustedInstaller-level Command Prompt to delete it.
The most common cause for Error 39 on Windows 10 and 11 is the setting within Core Isolation. This feature can block older or virtual drivers—like the one Mastercam uses for its HASP/USB licensing—to prevent unauthorized access. To disable it: Open Windows Security via the Start menu. Navigate to Device Security on the left sidebar. Click on Core isolation details . Toggle the Memory integrity switch to Off . Restart your computer to apply the changes.
Important: Check the box that says "Delete the driver software for this device."
Sometimes the virtual bus itself is fine, but Mastercam's official licensing handshake infrastructure is outdated. Go to the official Thales/Sentinel downloads page. Click -> Scan for hardware changes to force reinstall
To resolve this error and restore Mastercam functionality, users can apply the following methods: How to Fix USB Driver Error Code 39 - Matsusada Precision
, particularly if multiple instances of Mastercam were running during a crash. Creating a new Windows user account and launching Mastercam from there can verify if this is the cause. Google Groups Mastercam X7-2022 Virtual Usb Bus Error 39 - Google Groups
Simply uninstalling the driver often leaves traces. Open Command Prompt as Administrator. Run the following command to search for any Mastercam driver remnants in the Windows driver store:
Simply trying to update the driver often fails. A clean uninstall and reinstall is necessary. Yes/No Updated HASP Driver
Navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\ .
: Corrupted UpperFilters or LowerFilters keys in the Windows Registry can prevent the USB bus from loading correctly.
Download the Sentinel HASP/LDK Windows GUI Runtime (e.g., v8.x or newer) directly from Thales/SafeNet.
If you spot keys named or LowerFilters within the corrupted emulator string that contain missing dependencies, back up the registry key and delete those specific filter strings. Restart the PC. 4. Reinstall the Driver via Device Manager