First of all, I admit that I do not know if this is the best place to ask this question. As my problem appear to be with pdf files created by TeXMaker and TeXStudio (obviously from a LaTeX file), I am gonna give it a try. Here is the problem:
I make a PDF file with TeXMaker or TeXStudio and then try to put password on "editing" part of it using Adobe Acrobat XI. After putting a password, when I try to reopen that file, strangely I get the following error:
There was an error opening this document. The file is damaged and could not be repaired.
The I repeated the same process for a scanned document. I didn't run into any problem. It works just fine. I reinstalled my Acrobat XI and it didn't solve the problem. Is there any related setting in TeXMaker or TeXStudio that I'm unaware of? If it helps, I am using Acrobat XI on Mac OS 10.7.5