To prevent Error 39 from returning during future Windows Updates, implement these practices:
Note: This is a temporary fix. The error may return when you restart your computer normally unless you switch Windows into Test Mode permanently. Enabling Test Mode Permanently To keep the unsigned driver running continuously:
For Mastercam, this means Windows cannot properly communicate with the virtual bus that your USB license key relies on. Without this bus, the software will launch in (or fail to launch entirely).
Go to support. Do not use the driver from your Mastercam DVD. Mastercam X7-2022 Virtual Usb Bus Error 39
Navigate to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\36FC9E60-C465-11CF-8056-444553540000 .
Step 2: Manually Remove the Virtual USB Bus in Device Manager
In the context of Mastercam (ranging from legacy versions like X7 up to version 2022), the software relies on a USB hardware key (dongle) or an emulator to verify the software license. When you see this error, it is usually triggered by one of the following factors: To prevent Error 39 from returning during future
Once Windows boots up, check the Device Manager to see if the error is resolved. 3. Reinstall or Update the Virtual USB Driver
Restart your computer. Note: A "Test Mode" watermark will appear in the bottom-right corner of your desktop. Step 3: Completely Reinstall the Virtual USB Bus Driver
Common causes for Mastercam specifically: Without this bus, the software will launch in
Open , expand Universal Serial Bus controllers , and verify that Sentinel HASP Key and Sentinel USB Key appear without errors. Method 4: Update Virtual USB Bus Drivers Manually
At the bench, he dug deeper. He compared older driver versions saved in a dusty backup folder — remnants from previous dongle problems — to the new ones. A mismatch in the INF file’s device ID stood out: the newer driver referenced a virtual bus interface that the dongle wouldn’t present. In plain terms, the software spoke a different dialect to the hardware.
Hold down the while clicking Restart in your Windows Start Menu.