We see a couple of reports every day in the Feedback mailbox from users who say that the messages in their Web Mail Inbox disappeared. Since EarthLink never deletes messages from any user's Inbox, we take such reports very seriously. If this has ever happened to you, maybe this explanation will help.
In every single report I've ever investigated, the problem came down to a misunderstanding about how email software works. When we check the logs, invariably the messages were deleted by the use of an email software program like Outlook Express or TA Mailbox, that the user was running on their own computer (sometimes inadvertently), and not from Web Mail.
Could we ever actually lose someone's email due to a problem with our systems? Perhaps. But we go to great lengths to make this a very remote possibility. And I'm not aware of any case when it ever occurred. The mailbox was probably emptied by an email program like Outlook Express and the messages are sitting somewhere on a home or office computer, and therefore can't be viewed anymore in Web Mail. Sometimes another family member or coworker may have inadvertently run the email software that has your account set up, and they accidentally retrieved your messages unknown to you. And course, it could have been you, and you either forgot, or didn't realize how the two ways to check email were different. Again, check any computers that have your email account set up on them in an email software program like Outlook Express or Eudora.
When you check email using email software on your computer, the application uses what is called POP3 protocol to retrieve a copy of the messages from our server and put them on your local computer to be viewed by your email software. And unless you have changed the default settings of your software, it then deletes the server copies for you automatically. This is what is meant by "retrieving" your mail. Most email applications do this automatically when they are run, and then continue to do so on timed intervals unless you shut them down.
Web Mail on the other hand, is a way to view messages that are on our servers using your browser. And it does not make any local copies on your computer. So you can check Web Mail from multiple computers and see the same messages, plus any new ones that have arrived. We never automatically delete any messages from anyone's mailbox except Trash and Spam, which are cleaned periodically for your benefit. So when messages go missing from your Inbox, look on any computers that have your email account set up on them and you will probably find it.
If you often switch between using Web Mail and an email software application on your computer (perhaps at work and at home), you may want to set your software to leave the messages on the server. You can find help changing this setting here (scroll down). Then your messages will always be visible in Web Mail. If you do this you'll need to check Web Mail frequently to make sure your mailbox doesn't fill up and stop accepting messages.
UPDATE: here's a concise answer in response to a user's question, which may also be helpful.
And here's another article where I've updated this information and explained it in more detail.