1. Before doing anything to your current install, copy anything you want to keep for that version from your ".../Documents/Paradox Interactive/Crusader Kings II" folder (or wherever your saves, screenshots, mods etc. are stored on your system; henceforth the "Steam user directory") to a backup folder for safekeeping. Then wipe the Steam user directory for CK2 entirely.
2. Roll your Steam copy back to the desired patch through the Betas tab as usual. Run the game once to allow fresh files to populate in the Steam user directory; these are going to be settings configurations and DLC signatures.
3. Copy the game's local files to a new directory as usual.
4. This is where things get a little involved. You want to set up a new user directory for the copied game; otherwise it will still try (and generally fail) to read and write to and from the Steam user directory, which causes all sorts of problems we don't want to deal with.
--4a. First, create a new folder inside the copy's main directory, the same place where "CK2game.exe" and the game's .dll files should all be already. You can name it whatever you want, but I usually call it something like "userfiles" for convenience. (
Screenshot) This folder will be the "copy user directory." Copy the full file path for that directory.
--4b. Next, create a text file called "userdir" in the main directory. (
Screenshot) Paste the copy user directory's path into that text file (
Screenshot) and save the file.
--4c. Now move or copy the files and folders from the Steam user directory into the copy user directory exactly as they appear; don't create any subfolders. If you have any old saves and/or mods archived for this version of the game, go ahead and set those up in the appropriate directories as well; in that respect, the copy user directory should function for the copied game exactly like the Steam user directory does for the main install. The end result should look a little like this: (
Screenshot).
5. Now run the copy to make sure everything's in order. You should see the mods and/or DLCs you have in the launcher. If not, review steps 1 through 4 to make sure you didn't miss something, just in case. (If you did everything and it still doesn't work, please tell me; I might have forgotten something important myself.)
6. Optional but highly recommended: You may want to prune the DLC installed in the copy directory back to the ones that were "current" as of that particular patch; trying to run incompatible DLC will cause interesting new problems that we don't want to deal with, and this will help safeguard against doing that accidentally. Cross-reference the
DLC indexand the
patches list to figure out which files you need to delete; DLC are listed in release order, and the "major" DLC always come before any minor content packs for the same patch group. For instance, if you're using v2.4.5, then you can delete "dlc062" (Conclave) and everything after that.
7. Once everything's in order and set up just the way you like it, wipe the Steam user directory again, revert the Steam copy back to the current patch, and return all your file backups to their proper place.
One final note: You might also find
this thread over in CK2 Tech Support handy. It doesn't go into quite as much detail, but it does have more info on where you can find the Steam user directory for other OSes if you don't use Windows, among other handy little nuggets of information.