|Component:||Microsoft Exchange Extensible Storage Engine|
|Message:||<process name> (<process id>) <storage group name>Database ‘<name>‘: The database engine lost unused pages <number>–<number> while attempting space reclamation on a B-Tree (ObjectId <id>). The space may not be reclaimed again until offline defragmentation is performed.|
Some unused pages were lost when the database engine was attempting to reclaim space.
The space may not be reclaimed until offline defragmentation is performed, so perform offline defragmentation when convenient.
If the problem persists, contact Microsoft Product Support Services.