So I'm working on a game that started on 2017.3 that we successfully updated to 2018.2 and I'm trying to update it to the 2018.3 beta, however I'm having some sort of issue with .NET, scripts, or assets, or a combination of the three. I've gotten ProGrids, ProBuilder, and Post Processing Stack working through the Package Manager, but I can't get Polybrush running. There's no option for it in Tools. On top of THAT all our scripts have a warning under them that say "The associated script can not be loaded. Please fix any compile errors and assign a valid script." We were having this issue in 2018.2 but we fixed it by deleting TextMesh Pro. Any suggestions? We're still new to Unity.