Once resolved, prevent recurrence:
If Mastercam shows a "Virtual USB Bus (Error 39)" or the dongle isn't recognized, try this concise fix:
If still failing:
If you need exact driver links or step-by-step with screenshots, tell me your Windows version (e.g., Windows 10 or 11) and whether the dongle vendor is Sentinel/Hasp or SafeNet.
(Also invoking related search suggestions...)
Mastercam X7-2022 virtual USB bus error 39 typically occurs when Windows prevents a third-party driver from loading due to modern security features or registry corruption. This error is often associated with "MultiKey" or Aladdin HASP drivers used for software licensing. Primary Fix: Disable Core Isolation (Memory Integrity) The most common cause for Error 39 on Windows 10 and 11 is Memory Integrity
, a security feature that blocks drivers it deems incompatible. Matsusada Precision Windows Settings and navigate to Privacy & security (Win 11) or Update & Security Windows Security Device security Core isolation details Memory integrity Restart your computer for the changes to take effect. Alternative Fix: Registry Editor (Lower/Upper Filters)
If disabling security features does not work, corrupted registry values may be blocking the USB bus. , and press Enter. Navigate to the following path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\ Locate the specific folder for USB Controllers: 36FC9E60-C465-11CF-8056-444553540000 In the right-hand pane, look for UpperFilters LowerFilters Right-click and these values. Restart your PC Driver Specifics for Virtual USB Bus How to Fix USB Error Code 39 In Windows 10/8/7 [Tutorial]
To fix the Virtual USB Bus Error 39 for Mastercam (versions X7 through 2022), you typically need to address security features in modern Windows versions that block certain virtual drivers. This error indicates that Windows cannot load the device driver because it is either corrupted, missing, or blocked. Primary Fix: Disable Core Isolation (Memory Integrity) mastercam x72022 virtual usb bus error 39 fix
The most common cause for Error 39 on Windows 10 and 11 is the Core Isolation security feature, which prevents many virtual USB drivers from loading. Open the Start menu and search for Windows Security. Navigate to Device security on the left-hand sidebar. Under Core isolation, click on Core isolation details. Switch the Memory integrity toggle to Off. Restart your computer for the changes to take effect. Secondary Fix: Registry Editor (Remove Filters)
If disabling Core Isolation doesn't work, corrupted registry "filters" might be blocking the driver. Press Windows + R, type regedit, and hit Enter.
Navigate to the following path:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000
In the right pane, look for entries named UpperFilters and LowerFilters. Right-click and Delete both (if they exist). Restart your PC. Alternative Troubleshooting Mastercam X7-2022 Virtual Usb Bus Error 39 - Google Groups
A “USB Bus Error 39” in Mastercam X7 (or any software using a virtual USB dongle, like the 2022 version of the HASP/SafeNet emulator) usually means Windows cannot load the virtual device driver because its registry entries are corrupted or another driver is conflicting.
Here’s a focused review of the problem and the most reliable fix:
The Mastercam Virtual USB Bus Error 39 is a persistent but solvable issue rooted in Windows driver signing policies and legacy HASP conflicts. For versions X7 through 2021, enabling test signing and performing a clean driver reinstall resolves over 90% of cases. For Mastercam 2022, the error indicates a configuration mismatch, not a missing driver.
By following the diagnostic hierarchy—test signing, clean driver removal, old HASP cleanup, and registry permission repair—users can restore full license functionality without reinstalling Mastercam or Windows. Once resolved, prevent recurrence:
Need further assistance?
The "Virtual USB Bus Error 39" in Mastercam (typically appearing for older versions like X7 or when using virtual licensing/HASP tools on modern Windows) generally indicates that Windows has blocked a driver from loading because it doesn't meet security standards or has a corrupted registry entry .
The most effective fixes involve disabling Windows Core Isolation or cleaning the Registry. 1. Disable Memory Integrity (Most Likely Fix)
Modern Windows security features like Core Isolation (Memory Integrity) often block the older "MultiKey" or virtual USB bus drivers used by legacy software because they are not digitally signed to modern standards .
Action: Go to Windows Security > Device Security > Core Isolation details. Step: Toggle Memory Integrity to Off .
Restart: You must restart your PC for this to take effect. This is the primary reason why drivers that worked on Windows 7 fail on Windows 10/11 . 2. Remove Corrupted Registry Filters
If Windows still cannot load the driver after disabling security features, "UpperFilters" or "LowerFilters" entries in the registry may be blocking the USB class .
Registry Path: Navigate to:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 . If Mastercam shows a "Virtual USB Bus (Error
Action: In the right-hand pane, look for UpperFilters or LowerFilters. If they exist, right-click and Delete them .
Warning: Back up your registry before making changes. After deleting these, restart your computer to force Windows to re-enumerate the USB stack . 3. Reinstall Virtual USB Bus Drivers
If the above steps fail, the driver file itself may be "Bad Image" or improperly registered. How to Fix USB Error Code 39 In Windows 10/8/7 [Tutorial]
After deleting the value, close the Registry Editor and restart the computer to see if the issue is resolved. YouTube·MDTechVideos
The issue with older versions like Mastercam X7 is that the bundled driver is often too old for modern Windows.
Option A – Use Mastercam driver installer (recommended):
Option B – Manual install via .inf:
This error became widespread for three main reasons:
Important Distinction: