Mastercam+x72022+virtual+usb+bus+error+39+fixed ((install)) Jun 2026
Modern Windows security features can block third-party virtual drivers. This is the most common cause of Error 39.
If the device is not listed at all, try clicking "Action" at the top of Device Manager and selecting "Scan for hardware changes." If it still doesn't appear, you may need to manually add the legacy hardware, which is beyond the scope of this quick guide.
| Mastercam Version | Known Issue with Error 39 | Best Fix | |-------------------|---------------------------|-----------| | X7 (2013) | Windows 10 20H2+ blocks driver | Step 4 (Test Mode) + Step 3 (Registry) | | X9 (2015) | Driver signing expiry | Step 5 (Replace vusbbus.sys) | | 2018 | Conflict with USB 3.0 controllers | Step 2 + Disable xHCI in BIOS | | 2020 | Memory Integrity blocks | Step 1 (Core Isolation OFF) | | 2022 | Windows 11 native incompatibility | Step 6 (Hardware ID injection) |
After applying these fixes, check the again. The "Virtual USB Bus" should appear under "System devices" or "USB controllers" without any warning icons.
: Open Command Prompt as Administrator and run:
Method 1: Disable Core Isolation and Memory Integrity (Most Effective)
After this process, reboot twice before testing Mastercam.
Windows cannot load the device driver for this hardware. The driver may be corrupted or missing. (Code 39)
Fixing the typically requires disabling the Windows Core Isolation (Memory Integrity) security feature, which often blocks the specialized drivers used for HASP keys or virtual USB emulators. Direct Solutions for Error 39 1. Disable Core Isolation (Recommended)
Windows may have cached a corrupted driver signature database. Manually replacing the file bypasses this cache.
X7 often conflicts with newer Windows power management.
Right-click the Windows Start button and select . Locate the yellow icon next to Virtual USB Bus . Right-click it and select Update driver . Choose Browse my computer for drivers .
Uninstall the existing from the Device Manager.
: 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
Do not rely on Mastercam’s default installer—it often bundles the broken driver.
Modern Windows security features can block third-party virtual drivers. This is the most common cause of Error 39.
If the device is not listed at all, try clicking "Action" at the top of Device Manager and selecting "Scan for hardware changes." If it still doesn't appear, you may need to manually add the legacy hardware, which is beyond the scope of this quick guide.
| Mastercam Version | Known Issue with Error 39 | Best Fix | |-------------------|---------------------------|-----------| | X7 (2013) | Windows 10 20H2+ blocks driver | Step 4 (Test Mode) + Step 3 (Registry) | | X9 (2015) | Driver signing expiry | Step 5 (Replace vusbbus.sys) | | 2018 | Conflict with USB 3.0 controllers | Step 2 + Disable xHCI in BIOS | | 2020 | Memory Integrity blocks | Step 1 (Core Isolation OFF) | | 2022 | Windows 11 native incompatibility | Step 6 (Hardware ID injection) |
After applying these fixes, check the again. The "Virtual USB Bus" should appear under "System devices" or "USB controllers" without any warning icons.
: Open Command Prompt as Administrator and run:
Method 1: Disable Core Isolation and Memory Integrity (Most Effective)
After this process, reboot twice before testing Mastercam.
Windows cannot load the device driver for this hardware. The driver may be corrupted or missing. (Code 39)
Fixing the typically requires disabling the Windows Core Isolation (Memory Integrity) security feature, which often blocks the specialized drivers used for HASP keys or virtual USB emulators. Direct Solutions for Error 39 1. Disable Core Isolation (Recommended)
Windows may have cached a corrupted driver signature database. Manually replacing the file bypasses this cache.
X7 often conflicts with newer Windows power management.
Right-click the Windows Start button and select . Locate the yellow icon next to Virtual USB Bus . Right-click it and select Update driver . Choose Browse my computer for drivers .
Uninstall the existing from the Device Manager.
: 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
Do not rely on Mastercam’s default installer—it often bundles the broken driver.
