FormatException Invalid Image Format
Symptom
This error occurs late in the loading process or just after a city finishes loading:
FormatException: Invalid Image Format: failed to load
In the full stack trace, which can be found in the log file, you might see one or more of these:
AssetIcons.IconModifier.PatchIconsAssetIcons.IconModifier.OnLevelLoaded
Cause
This is caused by either of the following mods:
Those mods also cause Object reference not set to an instance of an object errors.
Solution
Completely unsubscribe the mods listed above - they are game breaking.
If you need a better alternative, we recommend Find It mod which is extremely reliable.
Was it Fixed?
If not, let us know - currently the mods above are the only known causes of the error, but it's possible there are other mods that cause it too.
Other issues? See: 👉 Troubleshooting