Corrupted development environment.

I have somehow corrupted my development environment. "Run and Debug" builds my watch app succeeds, but fails to run in the simulator on any device with:

I get a similar error in Eclipse.

I have to start the simulator from a terminal since neither Eclipse no VS fail to launch  the sim with "Unable to connect to simulator.", but this is a situation I have had intermittently for years, so I don't think it's the source of the problem.

I have failed to clear the problem reinstalling the SDK manager from scratch, first removing the cfg and ini files and going through the initial setup and downloading the device files.

I only have one version of the SDK loaded:

The devices appear to be correctly installed: 

Any suggestions as to my next step? Running on Mac

  • And now it's fine!

    After attempting all the possible ways of re-installing the Garmin development environment with no success, I cold restarted my Mac, including unplugging the power, reverted to an earlier SDK, 3.2.5, and hey presto all worked fine.

    Then restored SDK 4.0.7 and still everything fine.

    I suspect some gremlin in my Mac.