If it doesn't save with the launch options in place, definitely also make sure to whitelist cities.exe in your antivirus app. It may be blocking Cities from creating a savefile.
How To Set Launch Options
- Right-click on the game title under the Library in Steam and select Properties.
- Under the General tab click the Set launch options... button.
- Enter the launch options you wish to apply (be sure to separate each code with a space) and click OK. Should look like this:
-noWorkshop -disableMods - Close the game's Properties window and launch the game.