Microsoft Knowledge Base Article 910197 contains the following intoduction:

This article describes a behavior that may occur on Microsoft Windows 2000-based servers or on Microsoft Windows Server 2003-based servers that are running the File Services for Macintosh service. Macintosh volumes on Windows 2000-based servers or on Windows Server 2003-based servers will take more time to appear on the server after you restart the server. This behavior may also occur when the Services for Macintosh volume index is corrupted, and you have to restart the File Services for Macintosh service on Windows 2000-based servers or on Windows Server 2003-based servers.