If disabling Core Isolation does not work, the error may stem from corrupted "UpperFilters" or "LowerFilters" in the Windows Registry. These entries can prevent Windows from correctly identifying and loading the virtual USB bus required for Mastercam. Open regedit (Registry Editor).
Restart and reinstall driver.
The Error 39 Virtual USB Bus error typically occurs when Mastercam X7 2022 fails to communicate with the USB dongle or license manager. This issue may arise due to a corrupted driver, outdated software, or a conflict with other system applications. mastercam x72022 virtual usb bus error 39 fix