A lot of players report issues with the game crashing, frequently. The first time I played I didn't have any issues, but after that I began to get regular crashes, often losing entire games that I hadn't remembered to save. The game loads fairly quickly, so when I had saved I wasn't too irritated by the crash. However saving manually is tedious, especially due to the games clunky UI.

Fortunately, there is a hidden option to enable automatic saves. Here is how to enable it:

• Find the game in your Steam library, right click on it and select Properties.
  
• Under the General tab click the "Set launch options..." button.
  
• Enter the following and click OK: --ds
  
• Close the properties window.

Now when you launch the game you will have auto-save turned on. This will create a new save after every turn (including the AI turns) so if the game crashes you will lose only at most the last turn. These saves can build up very quickly, so you will want to clean them out occasionally. Again, the UI is too clunky to make doing this bearable, so I would suggest locating the directory "Documents/Catan/Savegames" (by default) and cleaning them out by hand.

There are a lot of people reporting issues with achievements not unlocking, or unlocking when they are not supposed to. Here are the ones I have worked out so far:

• Robber Baron - This achievement appears to unlock early. The description calls for robbing a player 10 times in a single game, but in practice you only need 10 times across all games.
  
• Outsourcing - This achievement unlocks if you finish a game of Catan without the Cities and Knights expansion enabled. Makes sense if you interpret the description literally, but is probably not what was intended.
  
• Brawn before Brains - This achievement also unlocks if you finish a game of Catan without the Cities and Knights expansion enabled.
  
• Knights of the Round Table - This achievement appears to unlock early. The description calls for playing a knight card 12 times in a single game, but in practice you only need 12 times across all games.
  
• Monoculture - This achievement isn't as hard as it may sound; you only need one hex adjacent to each of your settlements to have a common resource, you can still have other resources adjacent to your settlements. So, for example, build all your settlements next to a wood hex, and any other two hexes. This is quite easy to do, especially if you get the 2:1 port for that resource.

The following achievements appear to be broken, or at least don't work as expected:

• Roadblock - This didn't unlock when using a knight to break the longest road in the Cities and Knights expansion. I've attempted both breaking the road without taking longest myself, and with taking longest and winning at the same time. It is possible that building a settlement to interrupt longest road does work, I haven't tested this yet.
  
• On Principle - This does not work, despite multiple attempts to complete it. If there is a way to unlock this, the description is completely wrong.

Players are also reporting issues with the achievements Villager by Conviction and Lone Wolf not unlocking. Other achievements should work as described.

Thanks for reading this guide, I hope you found it helpful. If you have any information you wish to contribute which was not included already, please add it to the comments section so other players can see it. I will try to update and acknowledge contributions accordingly.