I had exact same issue installing openocd for stm32
I tried
- remove platformio and delete all files in my c:\user\name\.platformio
- re-install platformio
But No success.
So I manually download the package from here
Searched openocd files and downloaded file with name tool-openocd-windows_amd64-2.1000.190422.tar.gz
I extracted the file and copy paste into the package folder under .platformio folder
Now it is working!