We have identified an issue in SpatialOS 12.1. We are working on a resolution, but in the interim please use the workaround as described.
Environment: macOS and Unity v2017.x
The problem: Spatial may hang indefinitely when running
spatial worker build and
spatial worker clean from the CLI if Unity 2017 encounters an error during either of the steps.
As a workaround, use the build and clean options from Improbable -> Build menu inside Unity.