Event ID 623 occurs when you deploy Outlook 2010 in an Exchange 2003 environment

The Information Store service stops responding when you deploy Microsoft Outlook 2010 in a Microsoft Exchange Server 2003 environment.

When this issue occurs, an error message that resembles the following is logged in the Application log on the server that is running Exchange Server 2003:

This issue occurs because of changes to the nickname cache in Outlook 2010.

To resolve this issue, use one of the following methods, as appropriate for your situation.

Note Only follow these steps on client computers that are running Outlook 2010. Earlier versions of Microsoft Outlook do not store the nickname cache on the server.

Method 1: Decrease the number of allowed nicknames

Note We recommend that you use this method to resolve the issue that is described in the "Symptoms" section.

To resolve this issue, decrease the maximum number of nicknames that can be stored in the nickname cache. To do this, follow these steps:

1. Click Start, click Run, type regedit, and then press Enter.
2. Locate the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\AutoNameCheck
3. Right-click MaxNicknames, and then click Modify.
4. Type the maximum number of nicknames that you want to allow, and then click OK.
   
   Note There is no definitive number of allowed nicknames to resolve this issue. The number depends on the number of Outlook 2010 clients on the server, the size of the nickname caches on the clients, and how frequently the nickname caches are updated on the clients. We recommend that you use 300 as the starting value, and then decrease the value if it is necessary.
5. Exit Registry Editor.

Method 2: Change how frequently Outlook 2010 clients synchronize the nickname cache

To resolve this issue, change how frequently Outlook 2010 clients synchronize nickname cache changes to the server that is running Exchange Server 2003. To do this, follow these steps:

1. Click Start, click Run, type regedit, and then press Enter.
2. Locate the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\AutoNameCheck
3. Right-click NicknameLongTermSaveDelay, and then click Modify.
4. Type interval that you want, and then click OK.
   
   Notes
   • The NicknameLongTermSaveDelay value is stored in milliseconds. The default value is 10 minutes, or 600,000 milliseconds.
   • If you set the NicknameLongTermSaveDelay value too high, this may force clients to synchronize the nickname cache when Outlook 2010 is closed. In this case, the issue that is described in the "Symptoms" section may occur at the end of the business day. We recommend that set the NicknameLongTermSaveDelay value to a maximum of 2 hours, or 7,200,000 milliseconds.
5. Exit Registry Editor.

Method 3: Disable the Auto-Complete (nickname cache) feature

To resolve this issue, �you can disable the nickname cache feature by editing the registry or by changing the option in the Outlook user interface.

To disable the nickname cache featureby setting a registry value,�follow these steps:

1. Click Start, click Run, type regedit and then press Enter.
2. Locate the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences
3. Right-click ShowAutoSug, and then click Modify.
4. Type 0, and then click OK.
5. Exit Registry Editor.

To disable the nickname cache feature inthe Outlook 2010 user interface, follow these steps:

1. In Outlook 2010, click File and then click Options.
2. On the Mail tab, click to clear Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines.

In Outlook 2010, a temporary copy of the nickname cache is stored in memory on the local computer. A permanent copy of the nickname cache is stored in the Associated Contents table of the Inbox. The nickname cache is stored in an IPM.Configuration.Autocomplete message class and subject. By default, the nickname cache is synchronized to the server every 10 minutes if changes are made to the local copy. For example, the nickname cache is synchronized if items are added to or deleted from the local copy of the nickname cache.

Notes

• The nickname cache is synchronized to the server when Outlook 2010 is closed if Outlook 2010 is in Online Mode.
• In Microsoft Office Outlook 2007 and earlier versions, the nickname cache was stored on the local computer in .nk2 files.

The issue that is described in the "Symptoms" section can occur when the Exchange Extensible Storage Engine (ESE) tries to update the IPM.Configuration.Autocomplete message in the Associated Contents table. To update the Associated Contents table, the ESE blocks transactions against the Inbox until the update is complete. Because transactions are blocked, the messages are stored in Local Delivery queues. The messages that are stored in the Local Delivery queues cause the version store that is used to increase.

Typically, a mailbox stores approximately 1,000 nicknames. Therefore, an IPM.Configuration.Autocomplete message that is synchronized to the servers is between one megabyte (MB) and 1.5 MB. However, if many clients try to synchronize the nickname cache at 10 minute intervals, the issue that is described in the "Symptoms" section can occur.

For more information about the nickname cache in Outlook 2010, visit the following Internet website:

For more information about the nickname cache in Outlook 2007 and Outlook 2010, visit the following MSDN website:For information about how to troubleshoot version store issues related to JET_errVersionStoreOutOfMemory errors, visit the following TechNet website: