Please first try cleaning up any old data you may have. Uninstalling and reinstalling the game will not get rid of all the data from previous versions.
Be careful, because doing this will delete all your save data as well.
Backup any games you wish to save from Appdata and put them somewhere else, like on your desktop.
After backing up any important save games :
Navigate to your main game installation folder
Open the launcher executable
Click Tools, Clean game data, make sure ALL of the boxes are checked as in this picture:
Here is a video by one of the QA staff if you prefer a visual walkthrough (it does cover a bit more).
After that, verify the file integrity TWICE through Steam to ensure it catches any invalid files (sometimes it doesn't do it right on the first try). Three times to be sure.
If you continue to have issues, please create a new bug report with all the information necessary.