When email messages (that you have not deleted) go missing from
your Inbox, the most likely cause is that your email client is set
up to use POP, which is a protocol that downloads messages to your
computer while removing them from the email server.
To prevent email messages from disappearing from your Inbox in
the future, we recommend you configure your email
client to use IMAP, a protocol that leaves your email on the
Sometimes UB can restore email messages from your Inbox from
backups. To attempt to recover Inbox items, submit
a file restore request (login required).