I was running into this odd issue after upgrading to OS X 10.12 and nothing I would do seamed to resolve it. Tired tracking down error messages, reinstalling steam, changeling to beta and back, and other fixes. Ended up doing the following fix which straightened everything out.
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These works by Jeremy Pyne are licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License