Compare PDF (Adobe Acrobat) files FAQ

Can pdf files be opened without giving password?
Compare PDF demand password only if pdf file is protected with
password.

If you don't know the password you cannot open it with neither Adobe
Acrobat nor Compare PDF. 

I want to compare a pdf and same txt file, if is it possible?
Yes, Compare PDF can compare PDF and txt files (as well as well as
it can compare pdf and htm, or pdf and doc).

Compare badly structured Adobe Acrobat PDF files with MS Word DOC files.

Once you need to compare .pdf file with another one, you might have some problems with document structure and converting from PDF to text is uneasy task and resulted document is structured badly. AKS suggest some solutions that can help you do effective comparison of PDF document with .doc files or other.

Compare two or three column PDF files.

With Compare PDF you can compare PDF files that has two or three columns. It means that any PDF with columns can be compared to any word or .htm file

More information about comparing documents:

Compare documents after scan and OCR.