Event ID:602
Message:process name (process id) nameDatabase '%4': Background clean-up skipped pages. The database may benefit from widening the online maintenance window during off-peak hours. If this message persists, offline defragmentation may be run to remove all skipped pages from the database.
The background cleanup skipped pages. This message indicates that an offline defragmentation of the Information Store database should be performed. Offline defragmentation should be performed on each database separately.
User Action
Perform offline defragmentation of the Information Store database by using the Eseutil.exe utility with the /d switch to defragment the database file.

Note that the disk space required is equal to twice the size of the database being processed.

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