Same issue here. Removed all platformio packages, restarted, reinstalled, etc - same error:
PlatformIO: Terminal service is not registered.
‘Make sure that “platformio-ide-terminal” package is installed and activated.’
I can run ‘platformio’ in terminal just fine, just when selecting things like ‘Update platforms, packages and libraries’ from the menu it fails with that error. Rebuilding all platformio packages also didn’t help.
Did uninstall-reinstall everything (from Terminal package only to the whole Atom & PlatformIO), but nothing solved the problem.
Older thread recommended to install GCC which I did but did not help.
I didn’t use Platform-IO for a few days until today so I’m not sure since when it stopped working but I believe some auto-update got it broken as it used to work perfectly before.
MacOS Sierra 10.12.3
Atom 1.19.1 x64
PlatformIO 2.0.0-beta.8
Core 3.5.0a4
platformio-ide-terminal 2.5.5
I’m new to that kind of stuff and I had the same problem.
Take a look on the bottom right side … there is a bug-icon, click on it and choose “rebuild packages”, then restart atom and everything should be fine.