For some reason, the Virtual Com Port (VCP) drivers for STM32 chips were acting up and not properly enumerating a usable COM port on Windows when I was testing an STM32L476 chip.
The STSW-STM32102 software package contains four installation files based on the various versions of the Microsoft ® operating system. OS versions prior to Windows ® 7 are compatible with the Windows ® 7 installations included in the package. Starting from Windows ® 10, the STSW-STM32102 driver is no more adequate and the usage of the native inbox driver is recommended. Virtual COM Port Driver is typically installed in the C: Program Files (x86) STMicroelectronics Software Virtual COM Port Driver folder, but this location may differ a lot depending on the user's choice when installing the application.
I’m not sure if this is a chip-specific issue or if this problem shows up on more chips using the STM32Cube Hardware Abstraction Layer.
(Even after I installed Atollic TrueSTUDIO and the older STSW-LINK004 Windows utility, which I like better than the new STM32CubeProgrammer because it doesn’t require Java.)
The solution was to install an older Windows 8 VCP driver that they list on their website as part number STSW-STM32102.
The fun part is that the README file says “For Windows 10, use Microsoft inbox driver and not this package.“, which doesn’t do anything for me.
The 64-bit driver for Windows 8 works fine on Windows 10 and fixes the problem.
After installing the driver, the entry shows up in the installed programs.
And more importantly, the USB device enumerates correctly as a COM port in the Device Manager.
Stmicroelectronics Virtual Com Port Driver Windows 8.1
Good luck.