Missing emails in general

There can be several reasons why you did not receive an email:

Rebuild index/cache in Outlook

Occasionally, Outlook goes bananas while updating mails from a mail server, often due to errors in the local copy (called Global cache mode or the OST file).
Follow these steps to rebuild the OST file:

  1. Go to Tools -> Email Headers
  2. Select "View or Change existing email accounts", click Next
  3. Select "Microsoft Exchange Server", click "Change"
  4. Uncheck "Use Cached Exchange Mode", click Next, click Ok, and Finish
  5. Close Microsoft Outlook
  6. Open Outlook and turn on Cache again

Rebuild index/cache in mail.app (apple)

Engang imellem går mail.app i kludder mht. opdatering af mails fra en mail server, ofte er dette pga. fejl i det lokale index.
Den kan genbygges (rebuild) ved at vælge "Rebuild" fra Mailbox menuen

Occasionally, mail.app goes haywire while updating mails from a mail server, often because of errors in the local index.
It can be rebuilt by selecting "Rebuild" from the Mailbox menu.