How to remove password from PDF file?

Try to get to the original sender or owner of the file is the best way.

I will warn you, we generally do not touch anything about passwords so it is hard to say what kinds of responses you will get.

The originator (password owner) is your best resource. I have seen PDF mining programs destroy the information behind the password. Even the ones that purported to be able to mine the data on the other side of the password.

How important is this information?

If you're the owner of the PDF, then you must have the original document that the PDF was created from.

Get that document, recreate the PDF, and put in a new password that you can remember.

Seemples!

I had seen a sofeware was posted on other web site which is named pdf password unlocker,i think which can help you out of your trouble

this is the sofeware's link :

http://www.geardownload.com/security/pdf-password-unlocker.html

1 Use PDF Password Remover, just right-click the PDF file, select Remove Restrictions or Remove Restrictions & Save as... from the shortcut menu.
Here is the link:http://www.anypdftools.com/pdf-password-remover.html#153

2 Use PDF to Word Converter directly. As this coverter can remove the non- copy restriction when converting from pdf to eidtable word. Then you don't need to type word by word manually.
Here is the link: http://www.anypdftools.com/pdf-to-word.html#153

It is easy to remove password from PDF file with PDF Password Recovery 5.0.It works very well.
http://www.recoverlostpassword.com/products/pdfpasswordrecovery.html