MSExchangeIS 9519 (0xfffffb3a): Detected Multiple Databases With Same Signature In Use

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2007-01-23

The Microsoft® Exchange Database Troubleshooter Tool detected one or more MSExchangeIS 9519 events with error code 0xfffffb3a in the Application log. This error indicates that another copy of the same database is already running.


Each Exchange database has its own unique signature. If the Microsoft Exchange Information Store service detects multiple databases with the same signature, it will prevent the duplicate database from mounting.

The event can also be identified as error -1222, JET_errDatabaseSignInUse.

User Action

You can verify that two copies of the same database are present within a single storage group by following these steps:

  1. Dismount all other databases in the storage group, and try to mount the database that caused this error message.

  2. If the database is able to mount, you must then try to mount all the other databases in the storage group.

  3. If a different database in the storage group now gives the same error in the Application log, then two databases have the same signature; therefore, they are copies of the same database.

To resolve this issue, make sure that only one copy of the database is present within this particular storage group.