Is this an InDesign Library (created with File > New > Library), or is this a CC Library (new in InDesign CC)?
What version of InDesign? What operating system?
This is a none creative cloud library. So yeah he created it via File > New > Library. He is using CC 2014
Files get corrupted, and it sounds like this library is corrupted. I'd recreate it again. (There is a way of re-saving InDesign files as IDML, but no such method for a corrupted library that I've heard of.)
Ok I have recreated it. Cheers