Why do my emails keep disappearing?

Emails keep disappearing from different email clients?

• I have been using Microsoft Outlook 2010 and my emails have simply been vanishing from the account after opening them. I checked the rules and views set but everything seemed to be okay. After trying to reset all defaults with no success I decided to remove Outlook and try Thunderbird, the same problem is occurring so I have no idea what to do now.

• Answer:

  I believe Outlook doesn't download emails when you've already read them. So maybe you've been using an internet application to read your emails on another pc, and by doing that marked some of your mails read, so Outlook won't download them anymore and made it look like they just disappeared.