Array Index - Symptom 10
Symptom
You will see this error, or similar, on screen and in the log file:
Simulation error: Array index is out of range.
In the log file search to find the error above. On the line after that error, you should see something starting with:
at TerrainModify.ApplyQuad ...
or
at TerrainModify.UpdateAreaImplementation ...
Cause
We suspect this is caused by the outdated and game-breaking mods, namely:
Instead of Building Anarchy mod, you should use combination of both Ploppable RICO Revisited (activate relevant settings in RICO options before loading a save!) and Find It! mods. Alternatively Find It! in combination with Plop the Growables also works.
Instead of Terraform Tool 0.9 mod, you should use either vanilla terraform tools (in the Landscaping menu in-game), or, optionally, subscribe and enable the Extra Landscaping Tools mod which adds a few extra features.
Instead of Terrain Generator mod, use either vanilla terraform tools (in the Landscaping menu in-game), or, optionally, subscribe and enable the Extra Landscaping Tools mod to sculpt terrain in-game or map editor
Other possible causes (not verified but worth considering):
It could also be due to one or more mods not being compatible with 81 Tiles mod. Many older mods assume that your whole city will be within the central 25 tiles.
Old mods that alter zoning around roads -- see also: Array Index - Symptom 5
Solution
Completely unsubscribe Building Anarchy, Terraform Tool and Terrain Generator mods
Don't just disable them; they need to be completely removed so unsubscribe them
Exit game to desktop
Relaunch game and see if the error has gone
There might be some left-over side effects due to faulty terrain glitches or broken buildings on the map in your save game. If that is the case:
If you haven't already done so, subscribe and enable Loading Screen Mod (LSM)
In its mod options, enable the Safe Mode options
Load your save game
Assuming it works:
Broken building should just automatically despawn
If there are terrain glitches, use "Smooth" or "Flatten Terrain" tool to fix (you can find those tools in the Landscaping menu in-game).
Save the game under a new file name
Exit to desktop, relaunch then load the new save file - should now hopefully work properly :)
Was it Fixed?
If not, see other causes of Simulation error Array index is out of range.
Other issues? See: 👉 Troubleshooting