Simulation failed Deserialization tag mismatch
Symptoms
This error usually appears on the loading screen (if using Loading Screen Mod), or as an error popup after a city loads, or in the game log.
The word in brackets (e.g. VehicleManager) may change depending on the root cause of the error.
Causes
These errors are not caused by TM:PE.
There are two known causes of the error:
VehiclesManager- the city requires More Vehicles modAreasManager(or something about Areas / Tiles) - 81 Tiles mod is missing, or corrupt data
Solutions
If the error mentions VehicleManager:
Subscribe and enable More Vehicles mod
The city should now load (so long as you don't have any mods that are incompatible with More Vehicles)
If the error mentions Tiles or Areas then it is likely an issue with 81 Tiles:
Subscribe and enable 81 Tiles mod
Try loading the city - if you still get a tag mismatch, try the button in 81 Tiles mod options
In both cases, make sure you don't have any incompatible mods: Compatibility Report
(Thanks to BloodyPenguin, Dymanoid, AquilaSol and 夕林樱花Adonis for info about these errors)
Was it Fixed?
If not, there's probably no way to recover the city, unless you have backups of older saves?
Other issues? See: 👉 Troubleshooting