Virtual Usb Bus Error 39: Mastercam X7-2022
The "Mastercam Virtual USB Bus Error 39" is a classic case of Windows security evolution outpacing legacy industrial software. While the error message looks catastrophic, it is merely a driver handshake failure—not a dead license or broken hardware.
By methodically purging old driver remnants, reinstalling the correct CodeMeter runtime, and temporarily bypassing driver signature enforcement, you can resurrect your Mastercam X7 through 2022 installation. However, consider this a warning shot. The permanent solution is planning a migration to Mastercam 2023 or later, where the phantom "Virtual USB Bus" no longer exists.
Until then, keep this guide bookmarked. When a Windows Tuesday patch breaks your Monday morning CAM session, you will know exactly how to fight back.
Disclaimer: Mastercam is a registered trademark of CNC Software, Inc. This article is for educational troubleshooting purposes. Always maintain a valid software license.
The "Virtual USB Bus Error 39" in Mastercam (X7 through 2022) typically indicates that
Windows cannot load the required device driver because it is either corrupted, missing, or blocked by security features
. This error is common when using virtual USB emulators or physical HASP keys on modern versions of Windows. Common Causes Core Isolation/Memory Integrity:
A Windows security feature that often blocks older or unsigned drivers, such as those used for virtual USB buses. Corrupted Registry Keys:
"UpperFilters" and "LowerFilters" entries in the registry can interfere with USB driver loading. Driver Signature Enforcement:
Windows may prevent the driver from loading if it lacks a valid digital signature. Recommended Solutions 1. Disable Core Isolation (Memory Integrity) Mastercam X7-2022 Virtual Usb Bus Error 39
This is the most frequent fix for Error 39 on Windows 10 and 11. Matsusada Precision Windows Settings and navigate to Update & Security (Windows 10) or Privacy & Security (Windows 11). Windows Security Device Security Core isolation details Memory integrity your computer. 2. Modify Registry Filters
If disabling Core Isolation doesn't work, clear potentially corrupted registry filters. Back up your registry before proceeding. The Driver May Be Corrupted or Missing. (Code 39 Solution)
Mastercam X7-2022 : Fixing the "Virtual USB Bus Error 39" If you are seeing Error Code 39 while attempting to run Mastercam X7 Mastercam 2022
, your Windows operating system is likely blocking the Virtual USB Bus driver. This error typically states that Windows cannot load the device driver because it may be corrupted or missing. In the context of Mastercam, this usually points to a conflict with modern Windows security features like Core Isolation. Top Solution: Disable Core Isolation (Memory Integrity)
The most common cause for Error 39 on Windows 10 and 11 is the Memory Integrity 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.
Alternative: Registry Fix for "UpperFilters" and "LowerFilters"
If disabling Memory Integrity doesn't work, corrupted registry values may be preventing the Virtual USB Bus from loading. Press Win + R, type regedit, and hit Enter.
Navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\.
Locate the specific GUID for your USB device (look for one containing "Universal Serial Bus controllers"). On the right pane, look for UpperFilters and LowerFilters. Right-click and Delete these values. Restart your PC. Additional Troubleshooting Steps Mastercam USB HASP issue - eMastercam.com The "Mastercam Virtual USB Bus Error 39" is
The Mastercam Virtual USB Bus Error (Code 39) is a driver-related issue that prevents the software from recognizing the necessary security dongle (HASP) or virtual licensing key. It most frequently occurs on Windows 10 and 11 due to modern security features blocking older or non-digitally signed virtual USB drivers. Root Causes
Core Isolation / Memory Integrity: This is the most common cause in Windows 10/11. The security feature blocks drivers that it deems incompatible or unverified.
Corrupted Registry Values: Missing or corrupted "UpperFilters" and "LowerFilters" in the Windows Registry can prevent the USB bus driver from loading.
Outdated/Incompatible Drivers: Older versions of the Mastercam/Aladdin HASP drivers often lack the digital signatures required by modern Windows security protocols.
Windows User Profile Corruption: In some instances, a crash while multiple Mastercam sessions are open can corrupt the user profile, causing persistent startup failures. Recommended Fixes Expected Result Disable Core Isolation
Navigate to Windows Security > Device Security > Core Isolation details and turn Memory Integrity to Off.
Allows Windows to load the "incompatible" virtual USB driver. Registry Cleanup
Use regedit to locate the Class key 36FC9E60-C465-11CF-8056-444553540000 and delete UpperFilters/LowerFilters. Clears conflicting filter drivers that block the USB bus. Update Drivers
Download the latest HASP/LDK drivers from the official Thales (formerly Aladdin) support site. Disclaimer: Mastercam is a registered trademark of CNC
Replaces corrupted or unsigned files with verified versions. Recreate User Profile
Delete the affected Windows User Profile and log in with a fresh one.
Resolves application crashes linked to corrupted configuration files. Troubleshooting Checklist Mastercam X7-2022 Virtual Usb Bus Error 39 - Google Groups
The original driver is 32-bit only. You must:
Before you dive into fixes, confirm you actually have Error 39. You will see:
This error is especially common in Mastercam versions X7 through 2022 because these versions use a specific generation of SafeNet/Aladdin HASP drivers. Recent Windows updates (particularly Windows 10/11) often deprecate or block older, unsigned, or insecure drivers.
Common triggers:
If Error 39 points directly to the Virtual USB Bus (not the dongle itself), the bus driver is corrupted.
If your IT department forces Memory Integrity ON:
