Could you list an installed extensions? It seems that some extension breaks your IDE. Try to disable all extensions except of PlatformIO IDE + Microsoft C/C++ and check if it works.
i only use platformio and what ever it installs as a dependency.
on a clean install (1.26.1) with python minor .13 pre-installed causes the chain of installing pio to break. it installs up to the microsoft tools and just stops. pio may be ok with it on previous versions, but something is needed in python minor .15 to get it to work.
I loaded my options (including git option) before adding pio module. it would not activate the extension when the project was loaded. Again, removing that option is all that is needed to start it up.
hope this helps someone else.
Do you mean that it works with Python 2.7.13 and does not with 2.7.15?
It only works with vscode with 2.7.15. pio will work with 2.7.13 independently, but seems to be broken with the ide