When using WP-Filebase built-in PDF indexing mechanism, you might find a lot of error messages like “File has unbalanced q/Q operators (too many Q’s)” in your server’s log files, filling up the hard drive and keeping the CPU busy.

This is caused by to a bug in an old version of Ghostscript, occuring only with some PDF documents. Here are three options for a fix:

• Use our Advanced Indexing extension. It uses a webservice for indexing and does not require Ghostscript to be installed on your server
• Disable PDF indexing (just set the Ghostscript path to /bin/false), this will stop WP-Filebase from running Ghoscript at all, but PDF indexing is not available anymore
• Update ghostscript to >= v9.15. Try the package manager of your linux distriution first (such as apt-get upgrade). If this does not help compile Ghostscript from its sources

For more details about the bug see https://bugs.ghostscript.com/show_bug.cgi?id=693916

Versions known to have this bug:

• GPL Ghostscript 9.10 (2013-08-30)