Once you've updated your graphics drivers, restart your computer and try launching Medieval 2 Total War again.
If you are encountering this error while playing a mod (like Third Age or Broken Crescent), the issue is usually with the mod installation.
Overzealous real-time security scanning can block the game from reading script files, resulting in sudden desktop crashes.
Mods add hundreds of units. When you zoom out on the battle map, the game swaps high-detail 3D models for 2D "sprites" to save performance. If a modder forgot to generate sprites for a specific unit, the game searches for a file that doesn't exist and crashes.
This is often required for large mods like Stainless Steel or Third Age to prevent crashes during heavy battles. 2. Rename Executables for Steam Mods