This can happen when a user has a save file that contains modded content and the mod is removed from the computer (which can happen from the user deleting it or the creator of the mod removing or renaming it from the workshop). In the event that this doesn’t resolve the issue, a save file could be the culprit. Go to the Local Files tab and click on Verify Integrity of Game Cache.Right-click XCOM 2 and select Properties.Navigate to the game in your Steam Library.If you are experiencing difficulty launching XCOM 2 since the patch was applied, try verifying your game files through Steam.