email folders and emails have disappeared

Several folders with all the emails have disappeared from one of my email addresses.  I restore the backup, the folders reappear and then immediately disappear again.  I’ve tried this several times, tried changing settings, etc.  These are all my business emails from 13 years.  The webmail does not have these folders either (I never created them on the webmail, I thought they were local folders on my computer).    Please help.

Don’t know what is causing them to disappear, but there is a way to keep all those old emails.

Disconnect from the Internet and do a restore. Create some local folders, and move the emails to them. Reconnect to the Internet. 

Brilliant!  Thank you.