With Atom 1.12.0 on Mac (sierra) the build system don’t stop even when the build/upload is finished.
When starting building/upload i get following message:
The time counter of the build window is running endless.
The problem is gone with a new update of build v0.67
You are right, Atom 1.12 broke a lot of packages. Please go to settings page in IDE and update all installed packages.
We updated PlatformIO IDE Terminal for Atom 1.12 a few days ago.