This is a topic for which I’ve asked help also on dedicated ng, and for what I remember also the MVPes wasn’t able to help me. After some research and a bit of luck, I’ve finally found the solution.
Windows Vista has a powerful document indexer integrated into it, that is in charge to catalog all newly docs generated or saved into the PC, included e-mail and contacts inside Outlook.
Outlook 2007, installed on Windows Vista, use exclusively this indexer to scan through all the e-mails and contact when user queries for a specific topic, replacing the internal search engine function that is embedded within the product.
Along the past few months, I have had a little problem twice while using Windows Vista. I reformatted the PC and moved obviously all my data across the installation process, .pst files included.
As I did in the past, a simple copy to remote PC should be the only thing needed; but unfortunately starting from that moment, all my past e-mail and contacts seemed to not exist anymore when queried from the search toolbar. This was happening only for older elements, not the more recent ones.
At a certain point, I compared Outlook 2007 installed on Vista, and the same version installed on Windows XP. On the second there was a menu item missing (the one represented in the figure).
So I realized that the search query uses the indexing option built-in into the OS and that all the e-mail wasn’t correctly indexed. However, a button to start to reindex the e-mail inside Outlook wasn’t available. I was misled because of the previously mentioned menu item. In fact the “instant search” and “indexing status” button was suggesting me that, also by pressing the “indexing status” item, it always told me that no documents needed to be indexed.
Finally I realized that, just because the pst file wasn’t a new file – but a simple copy – the OS indexer didn’t correctly index it (or didn’t index at all).
I then entered into the control panel, “System and Maintenance”, then “Indexing Option”. The pop-up window appeared and I pressed the “Rebuild” button, into the “Troubleshooting” group.
At that point, a full reindex of all my hard disk has started again, and at the same time a reindex of the pst too.
Going back to the Outlook interface, I noticed that querying for an e-mail (rather than a contact) a tag line advised me that not all possible messages could return due to the re-indexing in progress (See picture below).
I left the text into the search box, and meanwhile the indexing process was going ahead, all the past e-mail start to appear. I finally pulled a sigh of relief, because it could not seek more in the old e-mail was indeed a problem.