If you are still seeing Code 39, you may need to roll back the specific Windows Update (KB5028185 or KB5030211 are known offenders for breaking virtual USB stacks).
Have a different error code? Let me know in the comments. Good luck machining!
Disclaimer: This post is for educational purposes regarding legacy software compatibility. Ensure you own a valid Mastercam license.
Important: Back up system restore point and export registry keys you modify.
A. Restart and simple checks
B. Reinstall/repair license drivers (Vendor-specific)
Examples:
C. Remove corrupted drivers and reinstall
D. Repair Windows driver store and system files
E. Check and clean registry filter drivers (UpperFilters/LowerFilters)
F. Reinstall Mastercam license components
G. Check services and permissions
H. Antivirus/Driver signature enforcement
I. If driver files exist but get blocked by Windows driver store corruption
J. Reinstallation of Windows USB Controller drivers
K. Last resorts
Since the old driver is unsigned, you must allow it to load.
Once fixed, protect your setup:
After 14 hours of forum-diving, Marcus found a cryptic post on a Russian CNC forum (translated):
"Error 39 on HASP virtual bus? Force legacy USB view. Use devcon to remove the bus, then manually assign a lower filter driver."
The real fix—dangerous but effective—required three steps:
For mastercam x72022 virtual usb bus error 39 fixed, follow this sequence exactly:
Disable Signature Enforcement → Uninstall old bus → Clean registry (delete Upper/LowerFilters) → Reboot → Install HASP 8.31+ drivers → Reboot → Run NHASPX diagnostics. mastercam+x72022+virtual+usb+bus+error+39+fixed
Do not skip the registry step—it is the #1 solution that forums miss.
Do not proceed if you are using a legitimate hardware NetHASP. This fix is specifically for software/Virtual USB environments for legacy X7/2022 builds.
The fix lasted 14 months until a Windows security update rewrote the USB class driver again. By then, Marcus had finally migrated to Mastercam 2024, but he kept an air-gapped Windows 10 LTSC machine with the hacked driver—just in case.
Error 39 remains a cautionary tale: Virtual USB buses are fragile illusions. When the OS changes the rules of reality, even a perfectly good dongle becomes a ghost. And sometimes, to fix it, you have to become a ghost yourself—editing registries, forging signatures, and whispering to the kernel in its own dark language.
Final technical summary for those who just want the fix:
| Step | Action |
|------|--------|
| 1 | Disable Secure Boot (temporarily) |
| 2 | Uninstall hidden "Virtual USB Bus (HASP)" device with driver deletion |
| 3 | Block automatic reinstall via pnputil /disable-device |
| 4 | Modify HASP INF to add LowerFilters key |
| 5 | Self-sign INF and add to Trusted Publishers |
| 6 | Registry: SkipDriverError39Check = 1 under the device instance |
| 7 | Re-enable Secure Boot (if stable) |
Warning: This is a deep hack. It works for Mastercam X7 (and similar older HASP-protected software) on Windows 10 22H2 and early Windows 11 builds. Not for production environments without rigorous testing.
Virtual USB Bus Error 39 in Mastercam versions (including X7 through 2022)
typically occurs because Windows security features or registry conflicts prevent the emulator drivers from loading properly Matsusada Precision Primary Fix: Disable Memory Integrity (Core Isolation)
Modern Windows versions (10 and 11) include a security feature called Core Isolation
that often blocks virtual USB drivers used by older software emulators. Start Menu and search for Windows Security Navigate to Device security Core isolation details Toggle the Memory integrity your computer. Secondary Fix: Registry Filter Deletion
If the driver is flagged as corrupted despite being installed correctly, you may need to clear "UpperFilters" from the registry. , and run as Administrator Navigate to the following path:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 In the right pane, look for UpperFilters . Right-click and select your system. Driver Refresh Steps
If the error persists after the steps above, a clean driver install is necessary: Uninstall Existing Drivers Device Manager
, right-click the "Virtual USB Bus" (often under System Devices or Universal Serial Bus controllers) with the yellow exclamation mark, and select Uninstall device Driver Signature Enforcement
: If you are using an unsigned emulator driver, you must boot Windows into Disable Driver Signature Enforcement mode to allow it to load. Reinstall Sentinel/HASP : Use the official Sentinel HASP LDK Runtime
to ensure the physical or base virtual components are current. Google Groups permanently? Mastercam X7-2022 Virtual Usb Bus Error 39 - Google Groups
The "Error Code 39" in Mastercam (typically related to the Virtual USB MultiKey or HASP drivers) usually indicates that Windows cannot load the device driver because it is either corrupted, missing, or blocked by security features. This is a common issue on Windows 10 and 11 due to enhanced security protocols like Memory Integrity. Core Solutions to Fix Error 39
The most effective fix for this specific Mastercam error involves adjusting Windows security settings or cleaning up registry filters. 1. Disable Core Isolation (Memory Integrity)
This is the most frequent cause for Virtual USB drivers failing to load. Windows security blocks drivers it deems "incompatible" with memory protection. Open the Start menu and search for Windows Security. Navigate to Device security > Core isolation details. Toggle Memory integrity to Off. Restart your PC for the changes to take effect. 2. Delete Upper/Lower Filters in Registry
If the driver itself is corrupted, Windows may have "stuck" filters in the registry preventing proper communication.
Press Win + R, type regedit, and hit Enter to open the Registry Editor. If you are still seeing Code 39, you
Navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36fc9e60-c465-11cf-8056-444553540000 (This is the standard class for USB controllers).
In the right pane, look for UpperFilters and LowerFilters. If they exist, right-click and Delete them. Restart your computer. 3. Reinstall Virtual USB / HASP Drivers How to Fix USB Error Code 39 In Windows 10/8/7 [Tutorial]
How to Fix Mastercam Virtual USB Bus Error Code 39 (X7–2022) Encountering the Virtual USB Bus Error 39
in Mastercam (X7 through 2022 versions) can bring your production to a standstill. This error typically signifies that Windows cannot load the device driver because it is either corrupted or missing. Frequently, it is caused by modern Windows security features or registry conflicts.
Below is a comprehensive guide to resolving this error and getting your HASP back online. 1. Disable Core Isolation (Memory Integrity)
The most common cause of Error 39 on Windows 10 and 11 is a security feature called Core Isolation
. This feature often blocks older or virtual drivers from loading. Open Windows Security Privacy & Security (Windows 11) or Update & Security (Windows 10). Navigate to Device Security Windows Security Device Security Modify Core Isolation : Click on Core isolation details Turn Off Memory Integrity : Toggle the switch for Memory integrity Restart Your PC : You must reboot for these changes to take effect. 2. Delete Registry UpperFilters and LowerFilters
If the error persists, there may be corrupted registry entries in the USB controller class that prevent drivers from initializing. , and hit Enter to open the Registry Editor Navigate to the following path:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 In the right-side pane, look for UpperFilters LowerFilters Right-click and these values. Restart your computer to allow Windows to rebuild these filters. 3. Reinstall Virtual USB MultiKey Drivers
In some cases, the virtual bus driver itself needs a fresh installation or an updated file set to match modern Windows security standards. Remove Existing Drivers
: Go to your Mastercam installation or MultiKey folder and run the remove.cmd remove.bat file as an administrator. Update Driver Files : Some users find success by replacing older
files in the MultiKey folder with updated versions designed for Windows 10/11. install.cmd
file as an administrator. When the Windows Security prompt appears, select Install this driver software anyway 4. Advanced Troubleshooting Tips Change USB Ports
: Sometimes simply moving the physical HASP to a different USB port can trigger a driver refresh. Disable Hypervisor-Enforced Code Integrity : In the Registry Editor, navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceGuard\Scenarios\HypervisorEnforcedCodeIntegrity and set the Check Antivirus
: Ensure your antivirus software isn't quarantining critical Mastercam or HASP driver files.
For more specific driver downloads, always refer to official sources like the Sentinel/SafeNet Support Page or contact your Mastercam Reseller for verified driver packages. Are you using a physical HASP virtual emulator , and did you recently install any Windows Updates Mastercam X7-2022 Virtual Usb Bus Error 39 - Google Groups
The Virtual USB Bus Error 39 in Mastercam (versions X7 through 2022) typically occurs when Windows prevents a third-party driver, such as the MultiKey or HASP emulator, from loading due to security restrictions or registry corruption. Below are the standard methods to resolve this error: 1. Disable Core Isolation (Memory Integrity)
The most common cause of Error 39 on Windows 10 and 11 is the Core Isolation feature, which blocks drivers that don't meet specific security standards.
Open the Start menu, search for Windows Security, and open it. Go to Device security > Core isolation details. Toggle Memory integrity to Off. Restart your computer to apply the changes. 2. Remove Registry UpperFilters and LowerFilters
Corrupted registry entries for USB classes can cause driver load failures. How to Fix USB Error Code 39 In Windows 10/8/7 [Tutorial]
The "Code 39" error for the Mastercam Virtual USB Bus (often associated with MultiKey or HASP emulators) typically indicates that Windows cannot load the driver because it is either corrupted, missing, or blocked by security features. This issue is common in Windows 10 and 11 environments due to increased security around unsigned or third-party drivers. Primary Cause: Core Isolation (Memory Integrity) Disclaimer: This post is for educational purposes regarding
The most frequent cause of Code 39 for virtual drivers in modern Windows is Core Isolation , specifically the Memory Integrity
setting. This feature prevents drivers that do not meet strict security standards from loading. Matsusada Precision How to Fix Windows Security from the Start menu. Navigate to Device Security Core isolation details Memory integrity Restart your computer to apply the changes. Matsusada Precision Alternative Solution: Registry Modification
If the error persists or you cannot access security settings, you can manually disable the integrity check via the Registry Editor. Registry Path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceGuard\Scenarios\HypervisorEnforcedCodeIntegrity : Find the value and set it to Legacy Fix : Some users resolve Code 39 by deleting UpperFilters LowerFilters
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 if they exist. Driver Reinstallation Steps
Introduction
Mastercam X7 2022 is a popular computer-aided manufacturing (CAM) software used for CNC machining. However, some users have reported encountering a "Virtual USB Bus Error 39" issue while trying to use the software. This error can be frustrating and prevent you from using the software effectively. In this guide, we will walk you through the steps to fix this error.
What is Virtual USB Bus Error 39?
The Virtual USB Bus Error 39 is a common error that occurs when the Mastercam X7 2022 software is unable to communicate with the USB dongle (also known as a hardware key or license key). The dongle is a small device that plugs into your computer's USB port and is used to authenticate the software license.
Causes of Virtual USB Bus Error 39
The error can be caused by a variety of factors, including:
Step-by-Step Solution
To fix the Virtual USB Bus Error 39, follow these steps:
Step 1: Troubleshoot the USB Dongle
Step 2: Update Drivers
Step 3: Disable Conflicting Software
Step 4: Clean the Windows Registry
Step 5: Reinstall Mastercam X7 2022
Step 6: Apply the Fix
Verification
After completing these steps, start Mastercam X7 2022 and verify that the Virtual USB Bus Error 39 is resolved. If you still encounter the error, you may want to contact CNC Software support or a qualified technical support specialist for further assistance.
Conclusion