Array Index - Symptom 11

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 one of the following:

• at TerrainManager.GetSurfaceCell ... (usually occurs when exiting game)

or

• Parameter name: index followed by at System.Collections.Generic.List ... (usually occurs when loading a game)

(Thanks to krzychu124 for discovering the cause of these errors!)

Cause

These errors are not caused by TM:PE.

They seem to be caused by using the "Unlock All Tiles" button in the options screen of 81 Tiles mod.

We recommend manually unlocking tiles (i.e. purchasing them one by one) in-game to avoid these errors.

Solution

If the log file contains the following line:

• at TerrainManager.GetSurfaceCell ...

...then you should be able to just exit to desktop, relaunch the game and load your save normally.

However, if the log file contains the line below:

• Parameter name: index followed by at System.Collections.Generic.List ...

...your save game is likely broken beyond repair.

However... There is a chance that disabling 81 Tiles mod, but leave it subscribed, will allow you to get your game running again, albeit limited to 9 tiles (or 25 tiles if you use a mod like Purchase It!).

tip

It might even be possible (not tested) to save under new name, exit to desktop, then reload Cities: Skylines and re-enable the 81 Tiles mod (make sure to turn any 25 Tiles mods off first though!) and reload the save? Give it a try and if it works please let us know as it will help lots of people!

Was it Fixed?

If not, see other causes of Simulation error Array index is out of range.

Other issues? See: 👉 Troubleshooting