Running Apple Mac OSX, and your system.log is filling up with
mdworker[473]: Unable to use font: no glyphs present.
/System/Library/Frameworks/ApplicationServices.framework /Frameworks/ATS.framework/Support/ATSServer[474]: Serious problems were found in font data while activating it.
/System/Library/Frameworks/ApplicationServices.framework /Frameworks/ATS.framework/Support/ATSServer[474]: You may encounter drawing or printing problems.
Well, it could be Spotlight trying to index a bad PDF file. To find the offending file with use lsof and the process id of the mdworker process
lsof -p 473
In my case it was a PDF from the hadoop 20.0 release
