I, too, have this problem. I believe I can reliably open the files with Skitch, however. Unfortunately, Skitch is not a desirable PDF viewer. Evernote appears to corrupt the PDF file BUT it's readable using the **Evernote** PDF reader. On Evernote's part this is either sloppy or deliberate; either way it's infuriating. Anyway, try opening the files with Skitch. It's my work around.