Exchange Server 2003 mailbox store does not mount when the mailbox store database reaches the 16-GB limit

When the mailbox store database in Microsoft Exchange Server 2003 Standard Edition reaches the 16-gigabyte (GB) size limit, the mailbox store does not mount. Additionally, the following event IDs may be logged in the Application event log:

Event Type: Error
Event Source: MSExchangeIS
Event Category: General
Event ID: 1112
Description: The database "Mailbox Store (Server Name)" has reached the maximum allowed size. Attempting to unmount the database.

Event Type: Warning
Event Source: ESE
Event Category: Space Management
Event ID: 445
Description: Information Store (3160) The database D:\Program Files\Exchsrvr\MDBDATA\priv1.edb has reached its maximum size of 16383 MB. If the database cannot be restarted, an offline defragmentation may be performed to reduce its size.

Note Although the description for event ID 445 states that the Priv1.edb file has reached a size of 16,383 megabytes (MB), this may not be true. Event ID 445 is triggered if the combined size of the Priv1.edb file and the Priv1.stm file reaches 16,383 MB. The Priv1.edb file by itself may be smaller than 16,383 MB.

For more information about MSExchangeIS event 1112 and ESE event 445, visit the Microsoft Web site: For more information about the improvements in database size limit configuration and management when you use Microsoft Exchange Server 2003 Service Pack 2 (SP2), see the topic Database Size Limit Configuration and Management (http://go.microsoft.com/fwlink/?LinkId=57029) in the Technical Reference Guide for Exchange Server 2003.

This issue may occur if the Exchange mailbox store database has reached the 16-GB size limit. The Messaging Database (MDB) shuts down automatically as soon as the mailbox store database has reached the maximum size limit. Additionally, the MDB will not restart when the mailbox store database has reached the maximum size limit. This behavior is by design to keep the system from trying to insert more data into the mailbox store database than the mailbox store database was designed to handle.

For more information about how to determine the server version of Exchange that is installed on the server, click the following article number to view the article in the Microsoft Knowledge Base:

To resolve this issue, use one of the following methods.

Method 1

To permanently solve this issue, upgrade to Exchange Server 2003 SP2.

For more information about the new database size limit with Exchange 2003 Service pack 2, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to obtain the latest service packs for Exchange Server 2003, click the following article number to view the article in the Microsoft Knowledge Base:

Method 2

If you are an administrator, you must perform the following tasks:

•	Temporarily increase the database size limit by 1 GB.
•	Selectively remove unnecessary database content.
•	Defragment the database to reduce the database to a level that is in the defined boundaries of the database size.

In Exchange Server 2003, the functionality to temporarily increase the database size limit by 1 GB is built into the product. However, to enable this functionality, the administrator must create the Temporary DB Size Limit Extension registry entry .

After you make create the Temporary DB Size Limit Extension registry entry, temporarily mount a mailbox store that exceeds the 16 GB limit. However, this is only a temporary solution. The next time that Exchange Server 2003 is started, the size limit reverts to 16 GB. You must reduce the size of the database before the size limit reverts to 16 GB. To reduce the size of the database, follow these steps.


Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
Note The registry value in this procedure is designed to enable a temporary increase the mailbox store database size limit. The registry value is not is designed for day-to-day operations.

1.	Add the Temporary DB Size Limit Extension registry entry to the computer that is running Exchange 2003 Standard Edition or Exchange 2000 Standard Edition. To do this, follow these steps: a. Click Start, click Run, type regedit in the Open box, and then click OK. b. Locate and then click the following key in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\<Exchange Server Name>\Private-<long hexadecimal string> c. On the Edit menu, point to New, and then click DWORD Value. d. Type Temporary DB Size Limit Extension, and then press ENTER. e. Double-click Temporary DB Size Limit Extension. f. Type 1 in the Value data box, click Decimal in the Base box, and then click OK. g. Quit Registry Editor.
2.	To prevent new e-mail content from being added to the mailbox store beyond the temporary 17-GB limit during the recovery process, we strongly recommend that you stop the Simple Mail Transfer Protocol (SMTP) service and the Microsoft Exchange MTA Stacks service before you mount the mailbox store.
3.	Mount your mailbox store.
4.	Remove data from your mailbox store. To do this, use one of the following methods: • Use Microsoft Outlook to delete unnecessary e-mail items from individual inboxes and other folders. • Use Outlook to delete unnecessary e-mail items from the Sent Items folder. • Use Outlook to empty the Deleted Items folder. • If a deleted item retention is set, you may want to temporarily reduce retention to zero (0) days: a. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager. b. Right-click Mailbox Store, and then click Properties. c. Click the Limits tab, and then type 0 in the Keep deleted items for days box. • Delete mailboxes that are no longer used. • Use the Move Mailbox tool to move mailboxes to a mailbox store that is on another server that is running Microsoft Exchange Server. • Have users create personal folder (.pst) files on their local hard disk drives. Then, have the users archive content from the mailbox store database to their local hard disk drives. • Use the Mailbox Merge Wizard (ExMerge) tool to archive content from the mailbox store database into personal folder (.pst) files. Note The ExMerge tool can archive the content by mailbox folder or by date range. For more information about how to use the ExMerge tool, see the Mailbox Merge Wizard (ExMerge).doc that is included with the the ExMerge tooldownload. To download the ExMerge tool, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?FamilyID=429163ec-dcdf-47dc-96da-1c12d67327d5&DisplayLang=en (http://www.microsoft.com/downloads/details.aspx?FamilyID=429163ec-dcdf-47dc-96da-1c12d67327d5&DisplayLang=en) For more information about permissions that are required for the ExMerge tool, click the following article number to view the article in the Microsoft Knowledge Base: 273642 (http://support.microsoft.com/kb/273642/) ExMerge does not work unless you have receive As and Send As permissions on the store
5.	After you remove data from your mailbox store, you must let online maintenance run so that items are marked for permanent deletion before you run an offline defragmentation. By default, online maintenance is scheduled to run every night from 1:00 AM to 5:00 AM. To force online maintenance to run immediately, follow these steps: a. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager to open Exchange System Manager. b. Double-click the Microsoft Exchange Server server, and then double-click Storage Group. c. Right -click Mailbox Store, and then click Properties. d. Click the Database tab, and then click Customize to modify the schedule to run immediately. Note Online maintenance may take 30 minutes to start and several hours to finish. When online maintenance has started, the following event ID message is logged in the Application event log: Event Type: Information Event Source: ESE Event Category: Online Defragmentation Event ID: 700 Description: MSExchangeIS (170) Online Defragmentation is beginning a full pass on database 'C:\exchsrvr\mdbdata\priv1.edb'.
6.	View the Application event log to verify that online maintenance of your mailbox store is finished. Event ID1221 indicates that online maintenance is finished. This event ID message also indicates how much free space there will be on your mailbox store after offline defragmentation. Event ID 1221 appears similar to the following event ID: Event Type: Information Event Source: MSExchangeIS Mailbox Store Event Category: General Event ID: 1221 Description: The database Storage Group Name\Mailbox Store has 565 megabytes of free space after online defragmentation has terminated.
7.	Run an offline defragmentation of your mailbox store by using the Eseutil tool (Eseutil.exe). You must dismount the mailbox store before you run an offline defragmentation. Additionally, you must have free disk space equal to at least 110 percent (%) of the database size to run eseutil /d. If you do not designate a temporary location for the database file by using the t command, the temporary location is automatically set to the Exchsrvr/Bin folder. In the example in this step, X is a temporary drive letter location for the defragmented database on the hard disk drive or on a network drive. After you run the eseutil /d command on your mailbox store, you must dismount all the stores in the storage group and remove any log files in the Mdbdata folder before you remount the database. The time to complete an offline defragmentation varies depending on factors such as the hardware involved or whether the temporary database is redirected to a network drive. The following command is an example of the command line that you use to run the Eseutil tool: exchsrvr\bin\eseutil /d "location of .edb file" /tX:\tempdfg.edb Note When you defragment an .edb database file, the associated .stm file is defragmented also. For more information about how to use the Eseutil tool, click the following article numbers to view the articles in the Microsoft Knowledge Base: 328804 (http://support.microsoft.com/kb/328804/) How to defragment Exchange databases 254132 (http://support.microsoft.com/kb/254132/) Eseutil /d defragments the database and the streaming file 192185 (http://support.microsoft.com/kb/192185/) How to defragment with the Eseutil utility (Eseutil.exe)
8.	Mount your databases, and make backups. WarningYou must perform a full backup of the databases after you use the Eseutil.exe to defragment the database. A full backup is needed because the database defragmentation creates new database files which have new database signatures. Log file replay after the restore depends on database signatures to match the expected values recorded in transaction log files. Any database backups that are taken before the defragmentation will contain database files that have signatures different from the new defragmented database. If an older database is restored, the new transaction logs which are bound to the new defragmented database files will not replay.

If you cannot upgrade the Exchange Server server to Exchange Server 2003 SP2, you may want to implement mailbox limits to help prevent the database from reaching the maximum size limit. You can implement mailbox limits on the mailbox store. If you have mailboxes that require more storage limits, you can also implement individual limits on a per-mailbox basis.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

The 16-GB size limit for the Exchange private mailbox store database and the 16-GB size limit for the Exchange public mailbox store database is the sum of the size of both the Priv.edb and the Priv.stm files. When you view the space that a mailbox uses in Exchange System Manager, the amount only includes the space that is used by the Priv.edb file. The amount does not include the space that the Priv.stm file uses.

When you put a limit on a mailbox, you only limit the storage in the Priv.edb file. You do not limit the storage in the Priv.stm file. For example, a mailbox may appear to use only 250 MB of space in Exchange System Manager, but the total space that the mailbox uses may be 450 MB. This difference occurs because the 200 MB of space that the Priv.stm file uses does not appear in Exchange System Manager.

For more information about this issue for Microsoft Exchange 2000 Server, click the following article number to view the article in the Microsoft Knowledge Base:
For more information about Exchange Server 2003 Service Pack 2, visit the following Microsoft Web site:

For more information, visit the following Microsoft TechNet Web site: