This is not about removing passwords that you don’t know from file – rather the process of removing a password which you do know from a number of pdf files. A client had a collection of workshop manuals of which some had passwords assigned but where the files were mixed in with other none password protected pdf files in various folders and sub folders. The one usefult thing was that the files with passwords all had the same password !!
Rather than manually trying to identify the affected files I located a utility from Axommsoft called PDF Restrictions Remover from here. This allows you to select the parent folder – scan all the pdfs and identify the ones that have passwords. Due to the size of the folders and the pdfs within I had to do this in several runs (the files were very large).
The application worked well although a few suggestions for improvement would be – all the files without passwords to be easily deselected and then only the remaining ones processed. This would have saved a lot of time. Also the layout could do with a facelift and the application should be able to go full screen especially where long file names and paths are involved.