I am running windows 10 version 1803 and I am unable to merge pdf files using PDF Creator Version 3.4.1. I am able to merge pdf's with version 2.1 but when I updated the software I am no longer able to merge documents. I do have the merge button with the # of documents but when I hit the button nothing happens.
Did you upgrade PDFCreator recently?
Please try a clean reinstallation: https://support.pdfforge.org/article/42-pdfcreator-reinstallation
If that doesn't do, you might need to take a look into the PDFCreator trace log: https://support.pdfforge.org/article/80-how-to-create-a-trace-log