Failed to connect to the simulator

Since yesterday, when a power failure to the area stopped everything, I have been unable to run the sim. All apps build but fails to proceed with "Failed to connect to the simulator".
No other apps appear to have been damaged.
I have tried
  • reboot the Mac - obviously reloads Eclipse
  • swap the SDK to an earlier version
Running Mac Mojave, SDK 3.0.5, Eclipse Oxygen.

Any other suggestions before I reinstall Eclipse?