Today I bought both season 2 and Mother Russia. I was excited to get in and play them, but instead of being allowed to open the game, I was greeted with this: I'm running on windows 10 and on the most recent version of TBW. The last time I opened the game before I bought the DLCs it did not do this so I assume the DLCs is the cause of this. I have tried reinstalling the game and verifying the integrity of the game cache but nothing changed. I have bought the base game and the DLC on steam so I don't know why this occurred. Edit: Problem solved. I just restarted my computer and now it is working perfectly fine. I'd still like to have an idea as to why this occured.
It's because of steam. If you buy something out from Steam, you might sometimes need to restart the client so it can sync up all the data with steam. In this case, you restarted whole computer which made Steam to sync the data again.