Redist or Common installation folders).After rebooting with Driver Signature Enforcement disabled:
To confirm the diagnosis, the following steps should be taken:
Verdict: A Necessary Evil for Legacy Users The "Virtual USB Bus Error 39" fix is not a piece of software you review for features or aesthetics; it is a utilityReviewed as a survival tool for running legacy versions of Mastercam (specifically X7 through X9) on modern Windows 10 and 11 operating systems. While it solves a critical problem, it requires careful handling regarding system security.
Key Insight: The dongle is physically fine. Your USB port is fine. The communication bridge (driver) is broken.
The Mastercam X7/2022 Virtual USB Bus Error 39 is a classic driver conflict, not a death sentence for your license. With the updated Sentinel LDK universal driver and a methodical cleanup of hidden devices, over 90% of users can restore their USB key in under 30 minutes.
Always remember: Mastercam X7 was built for Windows 7, so running it on modern Windows 11 requires the legacy driver tweaks in Methods 1 and 3. Mastercam 2022 is far more robust, but still vulnerable to Windows update conflicts. Bookmark this updated guide for the next time a Windows update tries to break your CAM workflow.
Have you fixed Error 39 using a different method? Share your experience in the comments below to help the Mastercam community.
Disclaimer: This article is for educational purposes. Always back up your registry and create a system restore point before modifying drivers. Mastercam is a registered trademark of CNC Software, Inc.
Virtual USB Bus Error 39 in Mastercam (X7 through 2022) typically occurs because Windows security features block the loading of older or virtual drivers, often flagging them as "corrupted or missing"
. This is frequently linked to virtual dongles or MultiKey emulators used for software licensing. Top Recommended Fixes Disable Core Isolation (Memory Integrity)
: This is the most common cause on Windows 10 and 11. These systems block drivers that do not meet strict security requirements. Windows Security Device Security Core isolation details Memory integrity Restart your computer. Registry Modification (UpperFilters/LowerFilters)
: Corrupted registry entries can prevent USB controllers from loading correctly. Registry Editor ) as an administrator. Navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 On the right side, find and UpperFilters LowerFilters entries if they exist. Restart your PC. Reinstall Mastercam/HASP Drivers : Sometimes the driver installation itself is faulty. Completely uninstall the existing HASP or Aladdin drivers. mastercam x72022 virtual usb bus error 39 updated
Download and install the latest versions directly from the official Mastercam support Check for Corrupt User Profile
: In some cases, repeated crashes while multiple Mastercam instances are open can corrupt the Windows User Profile. Creating a new Windows user account and testing Mastercam there may resolve the issue. Google Groups
: For those using virtual "MultiKey" or similar emulators, these are often incompatible with modern Windows updates unless specific 64-bit patches are applied or digital signature enforcement is disabled. disable driver signature enforcement to see if that allows the virtual driver to load? Mastercam X7-2022 Virtual Usb Bus Error 39 - Google Groups
The "Error 39" associated with the Mastercam Virtual USB Bus is a common headache for users running legacy versions of Mastercam on modern Windows operating systems. This error essentially means Windows cannot load the device driver because it may be corrupted, missing, or—most likely—digitally unsigned. The Root Cause: Driver Enforcement
The Virtual USB Bus is a software emulator used to bypass or manage physical Hasp/HL dongle requirements. Windows 10 and 11 require all drivers to have a verified digital signature. Since many virtual USB drivers for Mastercam X7 through 2022 are third-party "cracks" or unsigned emulators, Windows blocks them by default, resulting in the Code 39 status in Device Manager. How to Fix Error 39
💡 The most effective fix is disabling Driver Signature Enforcement. Step 1: Advanced Startup Go to Settings > Update & Security > Recovery. Under Advanced Startup, click Restart Now. Step 2: Startup Settings
Choose Troubleshoot > Advanced Options > Startup Settings > Restart. Step 3: Disable Enforcement
When the list appears, press F7 (Disable driver signature enforcement). Step 4: Reinstall the Driver Open Device Manager.
Find the "Virtual USB Bus" with the yellow exclamation mark. Right-click, select Uninstall device.
Re-run your driver installation script (usually install.bat or similar). Registry and File Integrity
If the driver is signed but still shows Error 39, the registry entry may be corrupted.
Check for UpperFilters/LowerFilters: Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class. Close the Registry Editor
Locate the USB Class GUID: Identify the string matching USB controllers.
Delete Corrupt Values: If UpperFilters or LowerFilters exist and are blank or contain invalid data, delete them and reboot. Long-term Stability
Using a virtual bus is often a workaround for missing hardware or license management issues. For professional environments, the most stable solution is:
Updating to the latest Sentinel HASP/LDK drivers from the official Thales website.
Moving toward Mastercam’s Software Licensing (standard in newer versions), which eliminates the need for a USB bus driver entirely. To help you get back to programming, let me know: Are you using a physical dongle or a software emulator? Which Windows version (10 or 11) are you currently on? Did this error appear after a Windows Update?
I can provide specific command-line steps if the manual reinstall fails.
The "Virtual USB Bus Error 39" in Mastercam (X7 through 2022) typically occurs when Windows cannot load the driver because it’s corrupted, missing, or blocked by security features like Core Isolation. The Story of the Ghost in the USB
Marcus stared at his screen, where a deadline for a critical milling job loomed. He’d just upgraded his workstation to Windows 11, but instead of the sleek performance he expected, Mastercam X7-2022 refused to launch. In the Device Manager, a yellow exclamation mark mocked him next to the Virtual USB MultiKey.
"The driver may be corrupted or missing. (Code 39)," the error read.
He tried the usual dance: unplugging the HASP dongle and moving it to a different port, but the error remained. He dug into the Mastercam user forums and found his first clue: Core Isolation.
The First Fix: Breaking the ShieldMarcus opened Windows Security, navigated to Device Security, and clicked on Core Isolation details. He flipped the Memory Integrity switch to Off and restarted his PC.
Upon reboot, the yellow exclamation mark was gone, but Mastercam still wouldn't budge. He realized his Windows User profile might have become corrupted after a previous crash while running multiple instances of the software. After rebooting with Driver Signature Enforcement disabled:
The Final Fix: The Registry CleansingDetermined, Marcus opened Regedit. He navigated deep into the system's class settings:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8098-00AA004C324E.
On the right, he found the culprits: UpperFilters and LowerFilters. He deleted them, closed the registry, and performed one final reboot. This time, as the desktop loaded, the HASP light flickered to life. Mastercam launched smoothly, and the "ghost" in the USB bus was finally laid to rest.
Fixing the "Virtual USB Bus Error 39" in Mastercam (versions X7 through 2022) usually involves
resolving a conflict between the driver and Windows security features or clearing corrupted registry filters Matsusada Precision 1. Disable Core Isolation (Memory Integrity)
The most common cause of Error 39 in Windows 10 and 11 is the Core Isolation
security feature, which blocks older virtual USB drivers like MultiKey or older Sentinel HASP drivers from loading. Matsusada Precision Start menu and search for Windows Security Device Security Core isolation details Memory integrity your computer. Matsusada Precision 2. Update Virtual USB/HASP Drivers
Ensuring you have the latest driver can sometimes bypass the need to lower security settings. Matsusada Precision Download the latest Sentinel HASP LDK Runtime from the official Thales (formerly SafeNet/Gemalto) support page Uninstall existing drivers via Device Manager
(under Universal Serial Bus controllers) before installing the new version. Microsoft Learn 3. Clear Registry "UpperFilters"
If the error persists, corrupted registry entries may be preventing the driver from loading properly. , and press Enter. Important: Back up your registry by going to File > Export before making changes. Navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 On the right side, look for UpperFilters LowerFilters . If they exist, right-click 4. Fix via "DeviceGuard" Registry Key
For some Windows 10/11 updates, you might need to manually disable the Hypervisor-enforced Code Integrity via the registry if the standard UI toggle doesn't work. Microsoft Learn In the Registry Editor, go to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceGuard\Scenarios\HypervisorEnforcedCodeIntegrity your system. Microsoft Learn manually reinstall the MultiKey virtual driver specifically for Mastercam? How to Fix USB Error Code 39 In Windows 10/8/7 [Tutorial]
The resolution involves manually removing corrupt registry keys associated with the device class to force a clean re-initialization of the driver stack.