This is the log from the launch after I renamed the save files folder. It's from the newly created folder, yet it still says that error.
I seems like your issues are caused by corrupt files in the steam cloud then.
You could check these steps to see if they solve your issues:
1. Go to
https://store.steampowered.com/account/remotestorageapp/?appid=949230 while logged into the same account used to play CSII with
Download all the files that the user wants to preserve to a safe location outside of the game user folder. Like C:\SteamCloudBackup or just their Downloads folder if they are not too precious saves.
2. Reset the steam cloud, this unfortunately may reset some achievement progress tracking and paradox login+friends of chirper entitlements will be reset if owned. It will be necessary to log in the paradox account again to re-unlock them.
Start the game with the command line toggles `--developerMode --qaDeveloperMode` (game properties>General>launch options)
In the main menu, press Tab and navigate to Platforms
Expand Remote storages and press `Wipe data` under the Steamworks entry (this will irreversibly delete all the content on the steam cloud so make sure to have downloaded the things wanted to backup)
Remove the launch options from properties, or at least `--qaDeveloperMode` as it exposes some dangerous operation that can wipe data unnecessarily
3. Restart the game, confirm the game works locally
4. (optionally) The downloaded save games from step 1 that are not corrupted can be recovered
Close the game
Copy the cok files of the desired saves to Cities Skylines II user folder (it can be at the root and the file will remain read-only or into Saves/<userSteamId> and it will behave like a local save)
Start the game, load the desired save game, save to Steam cloud again.
Corrupted files that show an error with reads out of bounds or missing central directory are unfortunately completely broken and these can not be recovered.
