FontDescriptionProcessor had unexpected failure

[TheKelsam]

FontDescriptionProcessor had unexpected failure!

A friend has downloaded my source code from the repo and, while trying to set up his environment, had 3 errors on his first build: Processor ‘FontDescriptionProcessor’ had unexpected failure! twice and "The command dotnet mgcb failed with code 2. I assume this is an environmental problem. Can anybody offer any suggestions that I can forward to him?