Database files on a Microsoft Exchange Server 2007 server cannot be extended. Additionally, the following event is logged in the Application Log:
This issue occurs because the NT file system (NTFS) fragmentation reaches the maximum size limit.
To resolve this issue, install the following update rollup:
Description of Update Rollup 3 for Exchange Server 2007 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.