Q:

Search not working in Preview.app

Viewing a pdf with Preview, I do cmdF to bring up a search box and then enter a word and hit enter.  
Basically nothing happens even if it's a word that's obviously present. Sometimes if I smash my hands all over the keyboard and spin around in my chair three times the search suddenly starts working again, but I haven't figured out how to do that trick reliably.

A:

I selected the "Table of Contents" in "View Menu" and searched again. It is working. Check the screenshot:

Anyway, make sure that your PDF contains texts and not the image of some texts.

A:

"BTW, in order to get search working again, you have to close the window (command + w) and reopen on the pdf. Closing Preview all together (command + q) and reopening the pdf doesn't work. This is indeed bizarre."
https://discussions.apple.com/message/33927812#33927812

A:

I've selected File->Export as PDF - reopened saved file and the Search worked.
Looks like some encoding issue.

