Compact Outlook Express prompts

I’m using Microsoft Office Outlook but I’m getting requests from Outlook Express to compact messages. The full prompts read;
“To free up disk space, Outlook Express can compact messages. This may take a few minutes.”

Why am I getting these prompts when I use Outlook and not Outlook Express and can I turn them off?

This happens when you install Windows Desktop Search on Windows XP. By default is it preconfigured to index Outlook Express as well. So when you install Windows Desktop Search to index your email in Microsoft Office Outlook, it will start indexing Outlook Express as well. When the search indexer stops the Outlook Express process, Outlook Express will prompt you to compact the message store every couple of days.

When you don’t use Outlook Express or simply do not want Windows Desktop Search to index Outlook Express, you can remove Outlook Express as a location that needs to be indexed. For more information on how to do that see this tip.