Last year when Adobe updated their software, they also included a protected mode in the software. Earlier password protected files were simple to open by just typing the password in the required field, but when I updated the software I couldnt open my bank statement as I was unable to type in the password as I used to do. Nothing was getting typed in the field even if I was trying to do the same.
Recently one of my friend faced the same situation as he recently updated his Adobe Reader and he couldnt view his credit card statement as he was unable to type in the password as nothing was happening. He called me up and I told him the solution, then later on he asked me to post the same here as it will be useful for many facing the same situation even though its just a setting change.
All of you should update the installed softwares on your computer to their latest versions to cover any security loop holes. Now whenever you open any password protected PDF file you see the normal screen as shown below, you type in the password and open your files but if you are using the latest version of the software simply typing the password wont help, even you wont be able to do the same, so just click on the cancel button
Now simply open the reader software, go to edit option and then click on preferences
Now in the General tab on the left hand side, uncheck the option enable protected mode at startup and click on ok
You will see a warning message as in the image below, just click on yes to apply the changes
Now open the document that you wish to view, type in the known password as you will be able to punch in the same this time. Do not forget to reverse the changes after viewing the document as leaving the settings as it is may leave your computer vulnerable because of the Adobe Reader software`s settings. If you keep on installing Adobe`s Reader and Flash software on different machines like me, you can download the offline installers to ease the installation process