Although this thread is a bit old I've run into issues with pdf ifilter on Windows 7 Ultimate x64 last week too. So this is not completely resolved over the years yet.
First of all: make sure your pdf's are searchable. This normally is only the case if you take a special action after creating a pdf (e.g. from a scanner). Some of the pdf's you'll receive from the internet or over the mail may be searchable. Others, however, will not. And most of the time you will not be able to make those externally gathered pdf's searchable. Bummer.
How do you check if a pdf is searchable? Just open it in Adobe or Foxit and search for some specific word that's in there. If it is found, the pdf is searchable.
OK, now for the ifilter.
Tried foxit ifilter first: download the right version (x64). There is no free version for desktop home use anymore, as far as I could find. Only a 30 day evaluation. After that you'll have to register or de-install. If you coincidentally uninstall Foxit ifilter before 30 days trial period has passed you may have a problem, since I could not reinstall the evaluation software after de-installation, even within the 30 day trial period. A bug they may fix.
I followed the installation manual Foxit provides. But could not get ifilter it to work properly since it would not index the contents of my searchable pdf's. Searched the web and tried all kinds of goofy tips for in total 25 hours (why do we keep doing this...). Yes I would get de pdf filenames indexed, but content I couldnt get indexed in any config I tried.
So out of frustration I decided to de-install Foxit Ifilter (as I stated above could not get it working on indexing content). Dissappointed, since the foxit reader is great.
Then decided to go Adobe and downloaded the Adobe ifilter from their site. Installed it according to the very simple instructions provided on the site.
Essential part of installation is to add the path to the ifilter dll's to the PATH environment variable of Windows. If this is jibberish to you, dont try to understand what that means, just do it.
For old school MSDOS veterans this is a jiffy, for newby users probably a bit puzzeling. Edit the PATH variable as instructed on their site: when editing the PATH variable first add a ';' at the end of the existing variable content and subsequently paste the 'C:\Program Files\Adobe\Adobe PDF iFilter 9 for 64-bit platforms\bin\' text behind de inserted ';'. Then push the save butten and you're done.
Of course you dont use the quotes in the text above, I used them here just for clarity.
Dont try to be smart to try to put in the text 'Program Files (x86)' instead of 'Program Files'. If you verify the dll-path before appending it to the PATH variable you'll see it normally is where Adobe tells you it should be (unless you customized the install yourself, and then you probably dont need my help here
Very important: then restart your computer. I also did a manual rebuild of the search index. Google it, and you'll get plenty of help on how to do that. And you get plenty of warnings about how long this normally will take to complete
. Which is normally true. On my desktop Windows 7 indexes over 300.000 items and that's not much since I took out a lot of search locations that I dont need to be indexed. On my very fast computer it takes a number of hours to complete. Which is very inconvenient if you want to test the if the pdf ifilter indexes correctly what it should and Windows search finds what it needs to find.
So, if you first want to see whether your searchable pdf's will be indexed correctly, you can temporarily change the search locations under 'Control Panel/Indexing Options' and then click 'Modify' to enter the search locations screen. Remove all search locations you dont need right now. Only configure the location where your searchable pdf's are. Maybe it's a good idea to create a small directory with just a few pdf's in it specifically for this test purpose up front and configure this as the only search location. This will greatly improve the time you need to try this out. And if it doesnt work well right away, then you can change something and the rebuild of the index with this test configuration is a matter of seconds, rather than hours.
If everything works fine after testing, dont forget to put back all the search locations and have the index rebuilt. Then leave your computer while it rebuilds the index and come back when it's done. Technically you dont have to leave your computer, but practically this will speed up the rebuilding process considerably.
Hope this helped.
The search locations screen is a good screen to go anyway even if you are not looking for ifilter stuff like in this item, because here it shows and you can change where Windows 7 Search will look for your files to be indexed. You can tune this to your own liking. Some of the locations seem to be bog standard, i.e. built in and you cannot remove them. But all your custom directories to look for pictures, films, email, word docs, searchable pdf's, etc. you can configure yourself.