thanks for your reply!

My second question is how to make outlook automcatically retrieve
mail from servers but not at the same time send messages that are
currently in the outbox. Generally, I want to receive automatically
but never send automatically.

Click ToolsSend/ReceiveSend/Receive Settings?Define Send/Receive Groups.
Select your Send/Receive group (usually "All Accounts") and click Edit.
Select each of your accounts and uncheck the "Send mail items" box.

The problem with this setting is that it affects both automatic and manual
send/receive. So if I uncheck "send", messages from that account are not
sent, even when I hit the send/receive button. I could define a second group
with the exact same accounts in it, but with different send/receive settings.
However, that would mean that every server is contacted twice when I manually
hit the send/receive button, which is slow. What I want is simply for Outlook
to automatically retrieve my mails and do nothing else.

And a third question: I'm used to receive notifications about calendar
entries via email. Is there a way to make outlook send me a mail
notification instead of popping up a window on the desktop? The
reason is that I'm looking at my mail frequently but a popup is gone
once dismissed, so I forget...

Outlook's reminders (without any third-party add-ins) are pop-up reminders.
I don't believe it can mail you a reminder. Your solution, however, is
simple: don't dismiss the reminder until you've addressed the calednar
event.

I'm afraid I'm very good at ignoring windows that hang around somewhere in
the background among the 30 or so other windows ;-)

thanks for your help!