The UserGuide currently is a real trouble maker. The PDFs exported from 2.2 or 2.3beta bring all PDFKit-based PDF viewers their knees in macOS 10.12. This also applies to the PDF downloadable from the LyX site. It does not happen in older versions of OS X nor with Adobe Reader and Safari or QuickLook or Foxit. The document kills Preview, Skim, PDF Expert, PDFPenPro. It opens with empty pages and while trying to scroll it then sends the affected application into endless beachballing. Curiously, just opening the UserGuide, and not scrolling it, effects other PDFs opened in this instance of the viewer. Whether they were opened before or after UserGuide has been loaded. Text will get very very blurry on scrolling and stays that way.
This is likely not the fault of LyX or LaTeX. Nevertheless, this is confirmed to happen – not on all but – on the clear majority of macOS Sierra systems tested. The bug has to lay within Sierra. So at least this is a heads up. Default PDF export on 10.12.6 opened in default PDF viewer Preview.app is likely fail. But I would like to know: Can somebody explain to me what makes either UserGuide so special of a PDF that this document triggers these symptoms? Other complex LyX PDFs like Additional or EmbeddedObjects seem OK. I tried to reduce the contents towards an MWE but I gave up just now. Preview.app being the most affected viewer doesn't really quit in Sierra. The process vanishes from human view but lingers in the process list. Until that background Preview is killed hard, all subsequent PDFs opened will be affected. greetings Mike
