This rollback procedure can be found on the Paradox Forums.
Be aware that the game is normally on automatic updates and once Man the Guns (version 1.6) is released, then version 1.5.4 saved games will not work unless the game is rolled back to the matching version. If the saved game version and checksum do not match the game version and checksum, then the saved game will not work. Saved games are set to the game version and checksum that are currently playing. Items 1 through 7 are as follows: 1) game version and checksum 2) video display button 3) clear user directory button 4) game play button 5) create account button 6) downloadable content (DLC) tab 7) mods tab.
It may be a good idea to become familiar with the information displayed, the various button and tab names, and the functions of those buttons and tabs before clicking the game Play button.
