Hi,
We like PDFCreator's Merge function and we've been using it for a while now. One thing we noticed is that emails that are printed from Outlook -> Microsoft PDF Printer have trouble showing up in Merge. To get around it, users need to cancel the merge then restart the merge again in order to see these files. I believe this is a possible bug and if this is something the Devs can look into, that would be awesome.
Thanks!
-Ted