Portable Document Format file! widely known as PDF file, is the most used format to share documents online. If you move back just a few years back, After the fist decade of 21st Century, the most common program to create documents online was MS Word. Though MS Word is still like a hot selling cake, but to send the files through mails or sharing through FTP, PDF has become a reliable option now. Sometimes due to corruption of PDF files it is not possible to open it. So before I tell you how to fix damaged PDF files you must know why it is preferred more than other formats.