Searching for LibreOffice files on Mac OSX
Spotlight won’t search inside LibreOffice documents on Mac OSX, any solutions?
It appears that indexing is something that regularly breaks, at least on the Windows platform (refer my answer here). The situation on MacOS is evidently not much different (refer fdo#38757 resolved as a duplicate of fdo#58663) although the reason appears to be 64bit compatibility. A possible solution is provided in the comments. If you could provide greater detail from you console, like what is given on the mailing list here, that may be of assistance. Also, please edit your question (or add a comment) to indicate which version of MacOS and LO you are using.
EDIT: As the comment by Alex below indicates, the new LO v4.2.x 64 bit build for recent editions of MacOS has resolved this issue i.e., fdo#58663 has been fixed.
Seems to work for me on OSX 10.9.3 with LO 4.2.x