The "Error Code 39" for the Mastercam Virtual USB Bus typically occurs because Windows security features, specifically Core Isolation, block the driver from loading. This error indicates that the driver is corrupted, missing, or more commonly in recent Windows versions, incompatible with modern memory protection. Primary Fix: Disable Core Isolation (Memory Integrity)
When you see Code 39 in Device Manager, Windows is telling you that the driver for this virtual bus is present, but its registry entries are corrupt, incomplete, or conflicting with another driver. mastercam x72022 virtual usb bus error 39 fix
Corrupted drivers are a frequent cause. A clean reinstall is often necessary. How to Fix USB Error Code 39 In Windows 10/8/7 [Tutorial] The "Error Code 39" for the Mastercam Virtual
Option A – Use Mastercam driver installer (recommended): Right-click the value → Delete
Even after uninstalling, old driver files may linger.
This is the standard fix for Error 39 involving USB devices. Warning: Editing the registry can be risky; back up your data first.