Did you check your references? It looks like you're copying the core RimWorld dlls as local references, which means the game basically tries to start twice.
In addition, I think you 'installed' harmony as a mod by just copying the files from github and putting it in the mods folder. Thats not how it works, you need to add the harmony dll to your references (and in this case, you do want it to be local). But honestly, you probably don't need harmony, and as a beginning modder, you probably should stay away from it until you know what you're doing. Harmony is immensely powerful, but if you don't know how to use that power it's just as easy to wreck things as it is to fix things.
In addition, I think you 'installed' harmony as a mod by just copying the files from github and putting it in the mods folder. Thats not how it works, you need to add the harmony dll to your references (and in this case, you do want it to be local). But honestly, you probably don't need harmony, and as a beginning modder, you probably should stay away from it until you know what you're doing. Harmony is immensely powerful, but if you don't know how to use that power it's just as easy to wreck things as it is to fix things.
.
) next to the mod to go to the GitHub releases page, where A18 versions will be marked as pre-releases.
