“Could not find a valid gem in any repository” (rubygame and others)
Check if you have “https://rubygems.org/” as a source to find gems at: $ gem sources *** CURRENT SOURCES *** https://rubygems.org/ If not, you should be able to add it with $ gem sources –add https://rubygems.org/ https://rubygems.org/ added to sources Here are docs for the gem source command.