Apparently there is a bug in the synctex library. Similar issues have been reported for other pdf viewers: Okular: https://bugs.kde.org/show_bug.cgi?id=383915 pdf-tools: https://github.com/politza/pdf-tools/issues/286 The synctex file and pdf from the first url also causes a crash with Skim 1.4.29, when one tries to do the backward search (it's a bit of random; you might need Shift-Command-click many times). Okular's issue seems to be fixed by updating the synctex library to version 1.19.