This article is a consolidation of the following previously available articles: 288894 and 328240
Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 Description of the Microsoft Windows registry
SUMMARY
This article describes a feature that you can use to disable MAPI client access to a Microsoft Exchange Server 2003 computer or a Microsoft Exchange 2000 Server computer based on the version number of the Emsmdb32 file. This feature was introduced in Microsoft Exchange 2000 Server Service Pack 1 (SP1).
This feature lets you restrict access based on any one or more of the following:
- A single MAPI client version
- A specific range of MAPI client versions
- An open-ended range of MAPI client versions
This functionality can help prevent problematic or beta client MAPI providers from running against an Exchange computer.
MORE INFORMATION
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.
To disable MAPI client access, you must create the
Disable MAPI Clients registry value. To do this, follow these steps:
- Start Registry Editor.
- Locate and then click to select the following registry subkey:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
- 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-
- Quit 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 only applicable for Exchange 2000 Server. In Exchange server 2003, changes to this registry key are dynamically detected. The following occurs inn Exchange 2003:- Every 15 minutes the store queries the registry key.
- If the registry key changes, these changes are immediately put into affect.
- 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.
Note 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-
v3 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- format.
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 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 one of the following files:
- Msmapi32.dll
- Mapi32.dll
- Outlook.exe
- Outllib.dll
For example, you have an Outlook client that has the following set of files:
| File name | Version |
| Outlook.exe | 11.0.6568.0 |
| Outllib.dll | 11.0.8001.0 |
| Msmapi32.dll | 11.0.6561.0 |
| Emsmdb32.dll | 11.0.8006.0 |
In this example, the version of Emsmdb32.dll that you can exclude or include is 11.0.8006.0.