I need to combine pdfs into one pdf document, but it says it will not allow 'conversion to pdf'

[Heatheraloha]

Hi! I need help! I am combining several pdfs into one large pdf file. As I am combining documents in Adobe, it suddenly has a warning exclamation point on one of my pdfs and says "Acrobat does not support one or more of your files conversion to pdf. Please remove these files or Go to settings and select the pdf portfolio option.'

Where is settings? How do I select this option? Why is it not letting me combine two pdfs, because the initial pdf is definitely a pdf...

[try67]

That usually happens when one of the files is secured or digitally signed. Try opening it on its own. Can you do it?

If so, does it say "SECURED" in the window title? Or does it appear to be digitally signed?

To change the way the files are combined you need to click on the Options button in the screenshot you posted and change the file type to Portfolio.