Thanks, this worked perfectly. Should become part of the help (at least, in German it is not there).

After sending a large mail and starting again, Pegasus 4.41 (German) starts and hangs up. Main window starts, parts of it (inbox in left pane) can be seen, status bar says "Filtering..." (dunno the English terms) and that was it. Program screen gets and remains white.

I'd really like to recover my mails (and I am willing to do all the config stuff again, if necessary).

[quote user="torstenrox"]

After sending a large mail and starting again, Pegasus 4.41 (German) starts and hangs up. Main window starts, parts of it (inbox in left pane) can be seen, status bar says "Filtering..." (dunno the English terms) and that was it. Program screen gets and remains white.

I'd really like to recover my mails (and I am willing to do all the config stuff again, if necessary).

[/quote]

Sounds like the mail has bounced and is hanging in the content control and/or filtering.

 Move all of the *.CNM files out of the new mail directory and try again.  It should now open normally.  You can then put the messages back one at a time until you find the problem message.  

It's probably going to be a really large message.  If you are using content control then I'd recommend that you set a limit on the message size so you are not scanning these large files with encoded attachments.

1.    Use  Tools | Spam and content controls | Content control...

2.    Select and edit the control definition

3.    Select the "Message tests" tab.

4.    Enter 8000 in "Check at most this many bytes in each message"