Applies to: yesSQL Server (all supported versions)


Attribute Value
Product Name SQL Server
Event ID 2515
Component SQLEngine
Message Text Page P_ID, object ID O_ID, index ID I_ID, partition ID PN_ID, alloc unit ID A_ID type TYPE has been modified but is not marked modified in the differential backup bitmap.


The page specified has a log sequence number (LSN) that is higher than the differential reference LSN in the BackupManager of the database, or the differential base LSN in the file control block of the file, whichever is more recent. However, the page is not marked as changed in the differential backup bitmap.

Only one page per database will be reported, because this check is only performed when the differential bitmap is known to be error free.

User Action

Look for Hardware Failure

Run hardware diagnostics and correct any problems. Also examine the Microsoft Windows system and application logs and the SQL Server error log to see whether the error occurred as the result of hardware failure. Fix any hardware-related problems that are contained in the logs.

If you have persistent data corruption problems, try to swap out different hardware components to isolate the problem. Check to make sure that the system does not have write-caching enabled on the disk controller. If you suspect write-caching to be the problem, contact your hardware vendor.

Finally, you might find it useful to switch to a new hardware system. This switch may include reformatting the disk drives and reinstalling the operating system.

Restore from Backup

If the problem is not hardware related and a known clean backup is available, restore the database from the backup.


If no clean backup is available, run DBCC CHECKDB without a REPAIR clause to determine the extent of the corruption. DBCC CHECKDB will recommend a REPAIR clause to use. Then, run DBCC CHECKDB with the appropriate REPAIR clause to repair the corruption.


If you are not sure what effect DBCC CHECKDB with a REPAIR clause has on your data, contact your primary support provider before running this statement.

If running DBCC CHECKDB with one of the REPAIR clauses does not correct the problem, contact your primary support provider.

Results of Running REPAIR Options

Running REPAIR will invalidate the differential bitmap. You cannot perform a differential backup until a full database backup is taken. The full database backup provides a baseline for the differential bitmap to be rebuilt.

See Also

Create a Full Database Backup (SQL Server)