Windows Update from late 2021–2023 intentionally blocks vulnerable drivers used by virtual USB bus emulators (like HASP/hardlock clones). Error 39 means “driver corrupted or missing” — Windows disables it because the driver is unsigned or flagged as incompatible .

Due to ongoing updates to Windows, community developers have released updated MultiKey drivers that are frequently updated to work around the latest security blocks. Using an outdated USB_Emul_Win64 folder from 2019 will almost certainly result in Code 39 on a modern OS in 2024/2025.

After disabling this feature, . Once rebooted, open Device Manager to check if the yellow exclamation mark persists.

Open by searching for it in the Start menu. Click on Device security . Select Core isolation details . Toggle Memory integrity to Off . Restart your computer for the changes to take effect. 2. Disable Driver Signature Enforcement

Below is a comprehensive, step-by-step guide to resolving the Code 39 error. The best practice is to follow these solutions in order, as they progress from simple quick fixes to more advanced system-level interventions.

Note: For Mastercam 2022, do not disable signature enforcement unless absolutely necessary; the LDK driver is already signed.

This report summarizes the issue of a Virtual USB Bus Error 39 encountered while using Mastercam X7 2022. The error occurred on a computer with a specific configuration, and the goal of this report is to document the problem, its symptoms, and potential solutions.

This is a known issue when using for Mastercam X7 (or older versions) on Windows 10/11 after certain security updates.

If you are still stuck after this guide, your last resort is to migrate your X7 license to a newer Mastercam version (2024 or 2025) that uses CodeMeter, as HASP support is now end-of-life. However, for thousands of shops still running legacy toolpaths on X7, the method above remains the gold standard.