Search within PDF files in Windows search

We have files on a server (just a plain Win7 server), when you search with different computers in the same folder, some computer find a result (that is within a PDF, in the text I mean) while others don't find anything.

I have check on all the computers in "Folder Options → Search → Search within files", and also installed that PDF iFilter thing but still it works on a few computer and others not. See images for example from 2 different computers:

What could be the problem / solutions ? Thanks for your help.

edit: maybe not unimportant, it WAS working on that computer that is now not working anymore. Maybe an Acrobat update or something caused the bug now ?

Solution 1:

(DO NOT INDEX ENCRYPTION. THIS METHOD WORKS FOR WIN 7 64 BIT)

Under no circumstance enable indexing of encryption. (Indexing Encryption will allow anyone who uses your computer to get passwords and personal information. Plus it can screw up the OS!)

1. Go to Indexing > Advanced > File Types, and remove the check for PDF. Press OK > Press Close

2. Uninstall any Ifilters that you have relating to searching PDF Files

3. Unless you have Adobe Reader 9.3 or higher, uninstall it.

4. Go to Adobe.com and install Adobe Reader 9.3 or Higher if not already installed.

5. Download and install Ifilter 9 from Adobe (Win 7 64 bit only) http://www.adobe.com/support/downloads/detail.jsp?ftpID=4025

6. Go back to Indexing > Advanced > File Types, and re-check PDF. The Press the 'Index Settings Tab' (THEN WAIT)

7. Try and keep all your PDF files in one folder.

8. Search for a PDF in the Windows search box (top right). You should see a message prompt near the top of the screen telling you that indexing is turned off, then asks you if you want to turn it on. Click the message and click to enable indexing.

9. Go back to Indexing, and click Rebuild (The rebuilding will take hours and will not work until it is done!)

If you did as I said above, you will be able to click on a start button and search for PDF files, and the contents inside them, including ones that you may have used OCR.