Zotero uses customized, platform-specific versions of the pdftotext and pdfinfo utilities from the open-source Xpdf project for PDF indexing, and stores text extracted from PDFs in plain text cache files.

If installation via the Search tab of the Zotero preferences window fails, you can try installing the utilities by hand.

Zotero uses modified binaries of pdftotext and pdfinfo on Windows to prevent the command-prompt window from appearing at indexing time, and a custom build of pdfinfo on all platforms that support writing to a text file (see source code).

Users wishing to install the Xpdf tools manually (or on platforms for which we haven't built customized binaries) can do so by building the tools and either placing the binaries directly in the Zotero data directory or linking to them from there. Either way, a platform-specific file must be created in the Zotero data directory, conforming to the format “pdftotext-{platform}”, where {platform} is “Win32”, “MacIntel”, “MacPPC”, “Linux-i686”, etc. (To determine your current platform, type javascript:alert(navigator.platform) in the Firefox URL bar and hit Enter.) The Windows version requires the .exe extension, i.e. “pdftotext-Win32.exe”. A text file containing the installed version number can also be created in the format pdftotext-{platform}.version.