Corrupted settings and cache can cause lots of trouble.
World of Tanks use a special folder to store the game settings and cache.
Should the game misbehave, do the following:
- Pres Windows key + R.
- Type %appdata%\wargaming.net\WorldOfTanks.
- Press Enter.
- The following folder opens:
- Preferences.xml – resets your game settings (graphics, audio, controls and so on.)
- Custom_data – force a client side refresh of your clan emblems.
- The rest – resets the game cache.
Should the issue persist, check this article.