I recently discovered that my 64 bit Windows 8.1 Search was not indexing the content of pdf files.  Since searching the content of pdf files is just about the only thing I want to do with a desktop search tool, it made the whole thing pretty pointless.  Fortunately the fix is pretty easy:

• Go to: http://www.adobe.com/support/downloads/detail.jsp?ftpID=5542 and download PDFFilter64Setup.msi.
• Run the download file
• Go to “indexing options” in Control Panel (you might need to search for “search” to get it to display).
• Click on Advanced, then the File Types tab
• Make sure that the check box next to pdf is checked, it displays “PDF Filter” next to it, and when the pdf file line is selected the “Index Properties and File Contents” button is selected, as shown below:

 A few more points:

• It seems that this problem has been around for years; it is beyond belief that it isn’t fixed yet.
• It may or may not also be a problem with 32 bit Windows.  Make sure you install the right filter for your operating system.
• Many reported “fixes” on the Web suggest editing the Registry, with mixed success.  I suggest trying the simple fix first.
• I wonder what Windows 10 will do to this.

And finally:

• When you get the index working, and want to do a search, don’t use the very un-charming Windows 8 search tool. Open File Explorer and use the search box from there.  You then get a full list of results which you can sort by date or name, and better still you can get a preview which opens near instantly, and can even be dragged to provide a readable image: