Trouble with installing mods

[stardropsyd]

I've been trying to install mods recently but I keep running into an error. I was watching a tutorial and everything seemed to be going good until I tried to run Stardew Valley. It doesn't matter if I run it from SMAPI or Stardew itself, it pops up with an error saying
Unhandled exception. System.TypeLoadException: Could not load type 'System.BadImageFormatException' from assembly 'System.Runtime, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.
at StardewModdingAPI.Program.Main(String[] args)
before disappearing quickly. I'm not sure what I did wrong.

 

[MysticTempest]

If it's throwing errors even when unmodded; it's an issue with game itself.
Try uninstalling, and reinstalling the game; then add SMAPI back.