This can happen if the stored message is missing the body or some important header and often it's the anti-virus that is interferring.  Make sure your a/v is not scanning the Pegasus directories while they are in use.

After a power outage, all email received into Pegasus email 4.52 is unreadable. Trying to open the email says the text is unreadable in a binary mode and some of the emails claim to be 50-400mb in size. I've deleted or moved everything in the new mail folder but all new mail received is still in binary form.

thanks,

Chris