[2022] Way to break the game with a update!

I'm really sorry for anyone affected, we are not able to reproduce the issue ourselves yet. Hence we need as much as information as any possible what is different for the affected people vs. the non-affected. Could you help us out with the following:

Do you start the game just normal via Steam? Have you set any parameters in the Properties (Right click)?

Do you start the world via ingame, e.g. "Your Worlds" -> Local Worlds -> Load? Or any other way? If you start the server via ingame means, can you try to manually start by executing /Steam/steamapps/common/Eco/Eco_Data/Server/EcoServer.exe, do you get the same issue then?

Thank you. To all of you as well: Do you use Steam only accounts or have you linked your Steam accounts with an SLG account?

As a workaround you can try the following?

Go to /Steam/steamapps/common/Eco/Eco_Data/Server/Storage and rename the .db and .eco file of the savegame you are currently playing to Game.db and Game.eco (note the capitalization!) respectively.

Then start the server manually via the EcoServer.exe (in /Steam/steamapps/common/Eco/Eco_Data/Server/). You will then be able to start the game and in Your Worlds, at "LAN Servers" you should be able to join it.

We have identified the issue and a hotfix will be available in about four hours. Thanks for your help.

This workaround should work for you until the hotfix is out:
Go to /Steam/steamapps/common/Eco/Eco_Data/Server/Storage and rename the .db and .eco file of the savegame you are currently playing to Game.db and Game.eco (note the capitalization!) respectively.

Then start the server manually via the EcoServer.exe (in /Steam/steamapps/common/Eco/Eco_Data/Server/). You will then be able to start the game and in Your Worlds, at "LAN Servers" you should be able to join it.

Alternatively you can link your Steam account to an SLG account on https://play.eco, that will solve it without the steps above being necessary.

No, that is corrupted files, the server didn't update correctly. Try to remove the /Mods/ folder and do another Steam update.