Currently, the game is storing the saves in a folder which is not automatically backed up by OS X. This mean reinstalling the OS or upgrading to Maverick for example will cause the save games and some settings not stored in the Steam Cloud to be lost.
Here are two options to avoid this undesirable scenario:
- When saving a game, it is possible to upload that save to the Steam cloud (by selecting the checkbox), so be sure to do it beforehand if you are going to upgrade.
- If there are too many save games and/or there are too big to store on the cloud, remember to copy your game data folder before upgrading. The folder can be found at the path "/<user>/Library/Caches/" under the name "unity.Colossal Order.Cities in Motion 2"