Before reinstalling, you must completely uninstall WhatsApp first.
Important information about your chat history: If you delete and reinstall WhatsApp, you will delete your message history. Click here to learn how to save your chat history.
On phones with physical keyboards:
On phones with touch screens:
If you are having a problem with WhatsApp, we recommend you first try updating WhatsApp from our website, before you uninstall and reinstall the app. You can learn how to update WhatsApp here.
Learn how to reinstall WhatsApp on: Android | iPhone | Windows Phone | BlackBerry | Nokia S60 | BlackBerry 10
Cheers,
WhatsApp Support Team