HELPROOM ANSWER The best way to get rid of this message is to let Windows do what it's after: compress the message store. This process has no adverse effect and will simply reduce the amount of space available on your hard drive for storing email messages.
To prevent the compression, however, first check that you are using the latest version of Live Mail. You can update your copy at . Open the blue 'Windows Live Mail' tab, then click Options, Mail, Advanced, Maintenance. Deselect the option to 'Compact the database on shutdown'.