This article is a consolidation of the following previously available articles: 288894 and 328240
To disable MAPI client access, you must create the
Disable MAPI Clients
registry value. To do this, follow these steps. Important
This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows
- Start Registry Editor.
- Locate and then click the following registry subkey:
- On the Edit menu, click Add Value, and then add the following registry value:
Value name: Disable MAPI Clients
Value type: REG_SZ
Value data: v1, v2-v3, -v4, v5-
- Exit Registry Editor.
- Restart the Microsoft Exchange Information Store service in the Services snap-in. Restart the Microsoft Exchange Information Store service in the Services snap-in even if you are in a cluster environment.
Note This step is applicable only for Exchange 2000 Server. In Exchange Server 2003, changes to this registry key are dynamically detected. The following occurs in Exchange 2003:
- Every 15 minutes, the store queries the registry key.
- If the registry key changes, these changes are immediately put into effect.
- If any current open connections are established with a newly blocked version, these connections are immediately disconnected.
- All new connections are blocked if you are using a blocked version.
This registry value is read only during the startup of the Microsoft Exchange Information Store service.
You can indicate all the specific versions or ranges of versions that you want to disable in this string. Use Exchange System Manager to determine the version of MAPI clients that connect to the mailbox store. In Exchange System Manager, locate the Logons container of the mailbox store. The Client Version
column displays the version of the MAPI clients that are connected to the mailbox store.Important
The MAPI client version is listed in Exchange System Manager as X.0.Y.Z. This version must be entered as X.Y.Z in the registry value. For example, if Exchange System Manager lists the MAPI client version as 5.0.2819.0, enter 5.2819.0 in the Disable MAPI Clients registry value.Important
Server-side Exchange components also use MAPI to log on. Some components report their client version as an Exchange build number. Therefore, avoid restricting 6.x.x on Exchange 2000 computers or on Exchange 2003 computers.
To disable a single MAPI client version
Enter the appropriate value in the Value Data string. For example, to disable the MAPI client version 5.0.2653.22, use the following string as the Value Data string for the Disable MAPI Clients registry value:
To disable a range of MAPI client versions
Use the v2
format, where v2
is the earlier version number that starts the range of MAPI client versions that you want to disable.
For example, if you want to disable the access of all the MAPI client versions from 5.0.2653.11 to 5.0.2653.22, use the following string value for the Disable MAPI Clients registry value:
To disable an open-ended range of MAPI client versions
Use the -v4
format or the v5
- format.To disable the MAPI client version v4
and all earlier versions, use the format -v4
. To disable the MAPI client version v5
and all later versions, use the v5
To disable multiple sets of MAPI client versions
Use any combination of the previous formats. Use commas (,) or semicolons (;) to separate the formats.
Error message that is displayed on blocked MAPI clients
After you configure the Disable MAPI Clients registry value, disabled MAPI clients receive the following error message when they try to connect to the mailbox store:
Cannot start Microsoft Outlook. The attempt to log on to the Microsoft Exchange Server computer has failed.
A Microsoft Office Outlook 2003 client receives the following error message:
Your Exchange Server administrator has blocked the version of Outlook that you are using. Contact your administrator for assistance.
To determine the MAPI client version for Outlook clients
The MAPI client version for Outlook clients is the version of Emsmdb32.dll that is used for the Exchange store or for the transport MAPI provider. The MAPI client version for Outlook clients is not the version of any of the following files:
For example, you have an Outlook client that has the following set of files:
In this example, the version of Emsmdb32.dll that you can exclude or include is 11.0.8006.0.