Why are my email folders disappearing?

Check internet connection.
Make sure your computer is connected to the internet. It is necessary for emails to be downloaded and stored.
See if you have mail accounts set up.
Open the email application or website and check for mail accounts.
Check for a data limit.
Your internet provider might have a limit on the amount of data you can use per month. Check your terms of service to see if a limit exists.
Reboot the computer.
This will refresh any applications, such as your email, that have been running.
Check the email settings.
Make sure the correct mail servers are set, and ensure the incoming and outgoing ports are correct.