Mastercam X72022 Virtual Usb Bus Error 39 Fix !!better!! [ Top-Rated - 2026 ]

The Virtual USB Bus Error 39 in Mastercam versions from X7 through 2022 is typically caused by a Windows security feature called Core Isolation (Memory Integrity), which prevents unsigned or older drivers from loading. Primary Fix: Disable Memory Integrity

This is the most common solution for modern Windows 10 and 11 systems where the driver is blocked by security protocols.

Open Windows Security: Search for "Windows Security" in your Start menu.

Navigate to Device Security: Select the Device security tab on the left-hand menu.

Core Isolation Details: Click the link for Core isolation details.

Toggle Memory Integrity: Switch the Memory integrity setting to Off.

Restart: Reboot your computer to apply the changes. The driver should now load without Error 39. Secondary Fix: Windows Registry (HVCI Disable)

If the toggle is greyed out or does not resolve the issue, you can disable it via the Registry Editor.

Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceGuard\Scenarios\HypervisorEnforcedCodeIntegrity Action: Set the Enabled DWORD value to 0. Restart: Reboot your PC after closing the editor. Advanced Troubleshooting

If the error persists after disabling Core Isolation, try these additional methods: How to Fix USB Error Code 39 In Windows 10/8/7 [Tutorial] mastercam x72022 virtual usb bus error 39 fix

Most effective fix (step by step)

  1. Uninstall the broken driver

    • Open Device Manager → View → Show hidden devices.
    • Expand Universal Serial Bus controllers or SafeNet Inc. devices.
    • Right-click the device with error 39 → Uninstall device → check “Delete driver software”.

  2. Clean registry entries (use with care)

    • Press Win + R, type regedit.
    • Navigate to:
      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB\
      Search for any key with “SafeNet” or “Virtual USB” and delete it.
    • Also check:
      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000
      Delete any UpperFilters or LowerFilters referring to the virtual bus.

  3. Reinstall the virtual USB driver manually

    • Download a clean copy of the emulator’s driver files (e.g., vusbbus.inf, vusbbus.sys).
    • In Device Manager → Action → Add legacy hardware → Install manually → Have disk → point to the .inf file.

  4. Disable driver signature enforcement (if on Windows 10/11)

    • Restart PC → press F8 or Shift+Restart → Troubleshoot → Advanced → Startup Settings → Disable driver signature enforcement.
    • Then reinstall the virtual USB driver.

  5. Prevent Windows from auto-updating the driver

    • Use gpedit.msc (Pro/Enterprise) or wushowhide.diagcab to block automatic driver updates for that specific device.

Fix 1: The "Driver Signature Enforcement" Bypass (Windows 10/11)

Windows 10/11 blocks unsigned kernel-mode drivers by default. Older Mastercam virtual bus drivers (pre-2020) often lack valid signatures.

Steps:

  1. Hold Shift and click Restart from the Start menu.
  2. When the blue screen appears, go to Troubleshoot → Advanced Options → Startup Settings → Restart.
  3. After reboot, press 7 or F7 to select "Disable driver signature enforcement."
  4. Log in to Windows, open Device Manager, right-click the error 39 device → Update driver → Browse my computer → Let me pick → Select the correct driver from the list.

Note: This must be repeated after every Windows update or major reboot. For a permanent fix, see Fix 7 (Test Mode).

2. Prerequisites & Safety Notes

Before proceeding:

Note for Mastercam 2022 users: Version 2022 uses CodeMeter (Wibu) for licensing, not the Virtual USB Bus. If you see Error 39 with 2022, you are likely running an older HASP-dependent legacy installer or a mixed license environment. The fix below still applies.

Preventative Maintenance: Avoiding Error 39 in the Future

Fix 2: Manually Reinstall the Virtual USB Bus Driver

Corrupted driver files are the #1 cause. Here’s how to force a clean reinstallation:

  1. Download the latest driver pack for your Mastercam version:

    • Mastercam X7–X9: Use HASP User Setup from the installation DVD or SafeNet’s legacy archive.
    • Mastercam 2021–2022: Use CodeMeter Runtime Kit (v7.60 or newer).

  2. Uninstall existing driver:

    • Open Device Manager → View → Show hidden devices.
    • Expand System devices → Right-click Virtual USB Bus → Uninstall device.
    • Check "Delete the driver software for this device."

  3. Clean driver remnants:

    • Open Command Prompt as Administrator.
    • Run: 
      pnputil /delete-driver oem*.inf /uninstall /force
    • Then navigate to C:\Windows\System32\drivers and delete vusbbus.sys, hardlock.sys, or cmudbus.sys if present.

  4. Reinstall fresh:

    • Run the installer (e.g., CodeMeterRuntime.exe or HASP_License_Manager.exe) as Administrator.
    • Reboot twice.

Step 3: Delete Stale HASP Driver Files

Even after uninstalling, old driver files may linger.

  1. Open File Explorer and navigate to:

    C:\Windows\System32\drivers\

  2. Look for and delete (or rename to .OLD) the following files if they exist: The Virtual USB Bus Error 39 in Mastercam

    • hardlock.sys
    • hasplms.sys
    • aksdf.sys
    • aksusb.sys
    • vusbbus.sys (This is the main Virtual USB Bus driver)

  3. Also check:

    C:\Windows\SysWOW64\drivers\

    (Delete the same files if found).

Preliminary Steps (Do These First)

Before diving into advanced fixes, run these quick checks:

  1. Run as Administrator – Right-click Mastercam launcher → Properties → Compatibility → Check "Run this program as administrator."
  2. Disable Secure Boot (temporarily) – Enter BIOS/UEFI and disable Secure Boot. Some virtual bus drivers require this.
  3. Uninstall recent Windows updates – KB5004237, KB5013942, and KB5026361 have broken virtual USB drivers for many CAM applications.

If the error persists, proceed step-by-step.

Step 1: Enable Test Signing Mode (Most Common Fix)

The Virtual USB Bus driver (vusbbus.sys) is test-signed. Windows blocks it unless test signing is on.

How to enable:

  1. Open Command Prompt as Administrator.
  2. Execute: 
    bcdedit /set testsigning on
  3. Restart your PC.

After restart, you'll see "Test Mode" in the lower-right corner of the desktop. That's normal.

Verification:
Open Device Manager → System devices → Virtual USB Bus (still showing error?). If yes, proceed to Step 2.

To revert later (after successful license detection): Most effective fix (step by step)

bcdedit /set testsigning off