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I occasionally come across some PDF documents which are unreadable on a Mac when using the standard OS X Preview. They work OK in Adobe Reader, but not in Preview.

Does anyone know what the cause of this is — in particular is there something we can configure to make these documents work in Preview?

Or is it a problem in the way the documents are encoded that makes it impossible to view in Preview? Maybe it is a deliberate misencoding of the document in a vain attempt to 'protect' it from being copied-and-pasted?

Here is an example document that causes the problem:

And here is how it looks in OS X Preview:

Garbled PDF Document in OS X Preview

I am using Preview version 5.0.3 which is part of Mac OS X 10.6.8. However the problem appears to have been going for a while. For example this forum post from 2009 lists a document that causes exactly the same problem on my computer.

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I've occasionally fixed this by copying the file and opening the copy, or saving as from Preview... – Dave Everitt Jun 22 '13 at 17:12

It may be a corrupt font cache. Use this command in the terminal to flush it and then reboot:

sudo atsutil databases -remove
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