According to the Diskeeper V7 Second Edition Build 430 readme:
 
"The Diskeeper NTFS boot-time engines have been
modified in this build to verify they have exclusive access
to the volume being defragmented. This change ensures that
no other drivers or services can modify the volume while the
boot-time defragmentation is running. If the volume cannot
be locked, an error message appears describing this and the
boot-time defragmentation will not run."
 
Prior versions of their NTFS boot time engine DIDN'T verify that they had exclusive access to the volume being defragmented 8)
 
How were they previously guaranteeing file system/data consistency ;(
 
I can certainly see why thy are strongly recommending that people update...
 
- Greg/Raxco Software
Microsoft MVP - Windows Storage Management/File System
 
Disclaimer: I work for Raxco Software, the maker of PerfectDisk - a commercial defrag utility, as a systems engineer in the support department.