PlatformIO: Intellisense Index Rebuild runs forever

The subject says it all.

Running on VSC 1.39 (because 1.40 has no tasks issue)
Ubuntu 19.10

Worked fine all day, just started while I was looking the other way.

Tried disconnecting from the internet, restarting VSC. Just sits there with the spinning beach ball.


What did you do to resolve this problem? I have the same issue on my existing project on Mac. But the project is being used on Windows by other developer as well. Thanks in advance.