Mir: Why doesn't anything appear when I apply Mir?

Typically nothing comes up when Mir is applied if:

• Mir is getting used on a system that doesn't meet the minimum requirements
  A graphics card (GPU) is needed with at least 2GB of dedicated video memory (VRAM) for HD projects, or 4GB for UHD (4k or higher) compositions. Intel GPUs unfortunately don't typically meet these requirements.
  
• Mir is getting applied to a large (>2k) composition
  The Far Vanish/Near Vanish settings are built around assumptions that Mir is getting used in an HD project. Adjust the Far Vanish/Distance settings of Mir to get Mir to appear in your composition.