Hm, the screenshot doesn't tell what's the problem only that there is a problem.
You can try the following:
Goto the Designer folder under your user profile (i.E. C:\Users\%Username%\AppData\Roaming\Adobe\Designer) and rename it (into Designer_old for example).
Then restart Designer, it will automatically recreate the Designer folder under your user profile.
If you'll be in luck Designer won't crash anymore.
If the problem still occurs you have to do a research in the event logs for more information.
Press Windows + R to open the run window, type in eventvwr and press Enter.
The app crashes are logged under Windows protocols > Application.