Preview.app does not update a pdf when it changes

Solution 1:

Try Skim. It has a preference option to check for file changes.

Solution 2:

The issue occurs when you have an error in your latex file. At that point pdflatex will delete the pdf, and preview will stop following it. After you correct the error, pdflatex will create a new file, but this will not be tracked by preview, which is still looking at the now non-existant file. This is why skim will work for a while as well. I understand why preview tries to follow the file, sort of, but I think this behavior is very annoying.

Solution 3:

The Skim app does not seem to automatically refresh the rendered PDF when I replace the PDF file with a new version, even with the "Check for file changes" preference option checked.

What does work with Skim is to select File -> Revert, then confirm the selection by clicking on "Revert" in the dialog box that pops up. This is way too manual for my taste.

Incidentally, the "Revert" menu option is grayed out when the PDF file has not been updated, but as soon as I update/replace the PDF file with a new version, the "Revert" menu option becomes available to be selected. So this indicates that Skim notices that the PDF file on disk is different than the version that was rendered, but it doesn't automatically refresh the display.