Milligoon also makes a good point.
Server AV software and MS Outlook also have "cleanup" programs these days, apparently they are meant to help us.....
These create folders and drop different things in.
It is possible to have a folder on the server which is NOT showing on your client as it has not selected it for display. Ask your email provider to check if all the folders you have on your outlook are on the server and vice-versa.
There are five languages from email server to client. When you setup your email this will be part of the language used to enter the username and password as well as provide the stability of the link.
1. Web mail (you use a browser to the hosted server) which should show everything.
2. POP3 (oldest and clumsy, avoid) which can hide new server side folders. Usable by almost all email clients. Don't flip from this to another without checking things first.
3. IMAP4 More efficient and secure but again depending on client may not display all folders. Usable by almost all email clients. Allows replication across many devices efficiently. Check with your provider if you use this setting on your client.
4. MS Exchange. Uses MS language from front to back and so you need to be using Office/O365/Exchange/Outlook. Good for logs and inspection. It should display all folders very well.
5. ActiveSync. This came in with mobile devices and is used mostly on them but new platforms (Mail app in Windows 10 for example) also offer it. It is an MS protocol and again this should display all folders in general.
HTH
