There's quite a bit of traffic on Apple's discussion boards (and others) about a problem with saving PDF files that have been viewed in Safari with Mountain Lion.
Safari can view PDF files just fine, but for many people the problems start when you go to save the files or print them. The files get corrupted, and you're met with a message that tells you the file is damaged. There is no problem viewing a PDF you already have in either Apple's Preview app or with Adobe Reader. If Safari is involved, however, you are likely to have some issues.
