PTVS cannot find Python environment, "+ Custom..." button greyed out

[kyanha]

I am having an issue where I cannot add a custom Python environment, because the "+ Custom..." button is greyed out. I had installed CPython 3.6, but that version was not listed in the dropdown list of the "+ Custom..." expando's version field when I attempted to set PTVS up to use it. I then quit Visual Studio 2015 Community, uninstalled CPython 3.6, and installed CPython 3.5. Ever since this happened I have been unable to fix the setup.

Is there anything I can do to fix this? Intellisense is not working and I really need it.

[r0f1]

Exactly my issue, a couple of days ago: Try this:

https://github.com/Microsoft/PTVS/issues/1994

[zooba]

Fixing the registry key mentioned in #1994 should resolve the issue, but it's sounding like we'll need to release another update for 2.2 to prevent this crash.

[zooba]

There is a 2.2.6 RC release at https://github.com/Microsoft/PTVS/releases/tag/v2.2.6-rc with the fix for this issue. Please try it out and let us know if anything goes horribly wrong - we want to push the fix to all users within the next month.