It sounds like your post is about an unexpected issue, crash, error message, or frozen game.
Start with our wiki article focused on basic troubleshooting to get you back up and running. If you're still facing issues, read up on the importance of log files and where to find them (you'll need these for the next steps).
If you play with mods, make sure that your mods have been updated for the latest version of the game or that you have swapped out to alternatives if mods you use have been abandoned. You should use Skyve to assist with this.
The best way to get personalised support with your game is to join the Cities: Skylines Official Discord server, find your way to the #cs1-tech-support channel, and complete the submission form. This will put you in touch with a team of experts ready to help you get back on your feet.
Be ready with copies of the log files detailed on our wiki. Without these files, even our experts on Discord will be unable to help you.
As the game has become more complicated, especially when playing modded, the number of reports necessary to help diagnose issues has increased. When coupled with Reddit's growing restrictions on links to file sharing services, it is now very difficult to reliably share these critical reports in a submission to the subreddit.
You're still free to ask for help on the subreddit, but you are more likely to have your problem solved via Discord.
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