How to Remove Protection From a PDF Fileby Jamie Lisse
If you have a PDF file on your computer that is protected so that you cannot open or edit it, you will need to remove the protection from that PDF file. If you did not originally create the PDF file, you will have to use some third-party software to remove the restrictions on the file. GuaPDF is a program that can be used in Windows, Linux and Macs to remove protection from PDF files. It is easy to use and quickly removes protection.
Open your Internet browser and navigate to the GuaPDF website (see "Additional Resources," below).
Download and install GuaPDF to your computer. You can get the free demo version or pay for one of the upgraded versions. GuaPDF works on Windows, Macs and Linux systems.
Launch GuaPDF on your computer. The "Choose A File" screen will open automatically.
Select the PDF file from which you would like to remove protection. Click "Choose" to select the file.
Watch the process screen as it analyzes the PDF and removes the protections for you. Click "Yes" in Windows to confirm that you want the protections removed from the file. Once it is done you will be able to click the "OK" button. Click it, and that will close the program automatically for you. You can then use the PDF file.