By Diane Poremsky
Let's start with some background on what search folders are and how they work. A search folder is a virtual folder that holds pointers to messages stored in other folders. They're not "real" folders, and any action you take on a message in a search folder will apply that action to the actual message in its folder.
For example, if you Select All then mark all message flags complete in the For Follow Up folder, the flags are marked complete on those messages in the Inbox. If you delete a message in a search folder, it's deleted from Outlook (or more accurately, moved to the Deleted items folder), the same as if you have deleted it from your Inbox.
When a search folder is created or accessed for the first time, it searches your mailbox and populates the folder with messages that match the criteria. It'll watch as new mail arrives and add it to the search folder if any matches the search criteria. It'll continue to do this as long as you make regular use of the search folder, and when you stop accessing the folder, Outlook stops looking for messages that match the criteria.
How often is "regular" use? As long as you access the folder at least once every eight days, the search folder will show all messages as they arrive. If you stop using the folder, Outlook will stop searching for messages to add to that folder until you begin using it again.
Outlook stops keeping a search folder updated after eight days of non-use because searching is resource intensive. If you aren't using a search folder very often, a saved Advanced Find search might be easier. You'll still need to wait for the search to complete, but since it runs in a separate window, you can continue working in Outlook while it searches.
Exchange administrators can configure the retention time for search folders in mailboxes, but standalone Outlook users are stuck with the default of eight days. Another limitation that can be changed by administrators is the number of search folders available. By default, you're limited to 20 search folders in an Exchange mailbox, but an administrator can raise (or lower) the limit for Exchange mailboxes by editing attributes in the Active Directory. Administrators can learn how to make these changes by reading the Microsoft TechNet article Best Practices for Search Folders.
While only Outlook 2003 has Search Folders, users of any version can save Advanced Find search as Office Saved Searches (*.oss). Copy the .oss file to any folder in your mailbox and you can initiate the search quickly and easily. Unfortunately, it's quite a bit slower than Search Folders because it doesn't cache the search results.
If you prefer a more Search Folder-like experience, try QSearchFolders. This add-in works with any version of Outlook, searching all folders or specific folders in the background, with search folders being updated automatically if the folders change, just as they are in Outlook 2003. QSearchfolders also supports all folder types, including Contacts; Outlook 2003's Search folders only support Mail and Post folder types.
