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 and performing a clean driver reinstall resolves over 90% of cases. For Mastercam 2022, the error indicates a configuration mismatch, not a missing driver.
Upon reboot, press or F7 to select Disable driver signature enforcement . Method B: Command Prompt (Permanent Fix)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 In the right pane, look for UpperFilters LowerFilters Right-click and these values if they exist. your computer. 3. Disable Virtualization-Based Security (Registry) mastercam x72022 virtual usb bus error 39 fix
Arjun deleted the UpperFilters key. He deleted the companion LowerFilters key for good measure. Then he opened Device Manager, right-clicked the “Mastercam X72022 Virtual USB Bus,” and selected .
Verify that and Sentinel USB Encryption Key are listed without yellow exclamation marks. The Mastercam Virtual USB Bus Error 39 is
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
(except keyboard/mouse) and test the Mastercam key. Upon reboot, press or F7 to select Disable
Most modern Windows 10 and 11 systems block older or unsigned drivers via a feature called Memory Integrity. Open from the Start menu. Navigate to Device security > Core isolation details . Toggle Memory integrity to Off . Restart your computer for the change to take effect. Secondary Fix: Registry Edit (DeviceGuard)
To fix the Virtual USB Bus Error 39 in Mastercam (X7 through 2022), you typically need to
The in Mastercam (spanning versions from X7 to 2022) typically indicates that Windows cannot load the virtual device driver, often flagging it as corrupted or missing. This issue is frequently caused by modern Windows security features like Core Isolation or residual registry filters that block the driver from initializing correctly. Primary Fix: Disable Core Isolation (Memory Integrity)
Before attempting any complex fixes, ensure all remnants of the problematic driver are completely removed from your system.