When I highlight text in OSX's Preview the size of the highlight becomes huge. These two images illustrate the problem (In the first image I am highlighting the text and the highlight is normal, in the second image you see the applied highlight which four-five times as tall): enter image description here


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However this does not happen with all PDFs. I am currently experiencing the problem with some PDF slides that most likely have been saved/exported/printed from PowerPoint (Windows). The problem is especially problematic when highlighting multiple lines, then the highlight becomes completely illegible (can't see which line it starts nor stops at).

Anyways of fixing this by myself? Or will I have to report it to Apple and then wait for a possible update/fix?


I have managed to fix the problem by using Preview to export the PDF file as a PDF. Somehow, doing so makes all the difference in terms of Preview's ability to recognize discrete lines of text that can then be highlighted normally.

  • This fixed it for me, not restarting Preview. – aledalgrande Nov 4 '15 at 22:23

I can't seem to avoid this problem, but I can get around it by restarting OSX Preview when it starts happening. When I reopen OSX Preview highlight works as it is supposed to (normal hight on highlights). Note: If I however save the PDF with a faulty highlight, the faulty highlight will still be there when I reopen the PDF – new highlight will work fine, but old ones are not corrected by saving and restarting OSX Preview.


I am pretty sure it is related to the actual PDF and not Preview itself, because my highlighter works fine on other documents. It's something to do with how the line spacing is set up probably, but maybe Apple could make a way to adjust that?

  • At first I also thought that it had something to do with the specific file/line height. But that cannot be the case when the 'faulty' highlight disappears if I save the PDF without the highlight, restart Preview, and then re-apply the highlight in the same file. – bonna Mar 10 '14 at 16:10

I have the same problem. It seems to occur only with PDFs that I have OCR'd with Adobe Acrobat. The same problem doesn't occur when highlighting the same file in other PDF readers, such as Skim. Quitting and restarting Preview does not help, in my case. Presumably, it's a Preview bug. I hope Apple fixes it.

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