You run the Exchange 2007 BPA and you get a warning for Disable MAPI Clients.

Disable MAPI Warning

Disable MAPI Warning

This warning is not a huge deal, as it has been present on my production Exchange server for months without causing issue. I HATE error messages though, and I am now getting around to getting rid of it.

You could go read the lengthy Technet article (linked here) or you could skip all the explanation and just fix it. Read on…

What this setting does is tells Exchange with versions of Outlook can connect to it. I have the pleasure of installing all of the office clients, so I know the lowest version of Outlook is 2007. I also know no one in the office connects to Exchange from Outlook at home (VPN or RPC over HTTPS) that is lower than 2007. So why would I let outdated clients such as 97, 98, 2000 or 2003 connect? I wouldn’t!

A list of client version numbers is here.

Warning: If you have older clients that connect using Outlook 2003 or 2k, you might not want to follow my advice.

Let’s see what sort of clients connect right now. Open up Exchange Management Shell. It will be in the Start Menu, under All Programs Exchange Server 2007.

Once it’s open, you need to navigate to the folder that has the scripts in it. Type in: cd “C:\Program Files\Microsoft\Exchange Server\Scripts” and hit enter (leave the quotation marks on). Now type get-logonstatistics



You get a long page, so lets put it in a text file to decipher by adding > c:\logon.txt. Reading the file tells us nothing, at least me anyhow. I blocked out the names to save identities.

So, I’ll look another way. Ill navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem registry value in regedit and read the value for DisableMAPIClients.

Mine is set to 0.0.0-5.3164.0, which is the default. I would like to restrict everything before Outlook 2007. So, reading the Technet article leads me to this value:


Warning: Back up all changes to the registry before you make them. Save the file with the date on it. If you break your box, it’s not my fault- registry changes can be dangerous.

I notice though that my Exchange does not want me to block version 8.x.x. So I will change that value to the lowest in the 9x.x range there is, which gives me:


This is telling Exchange to block ALL MAPI Access from client up to Outlook 2007, including Outlook 2003 SP3, excludeing ESA and Outlook 2007, 2010. This excludes a few numbers between 5.x.x and 9.x.x. This is because the Exchange System Attendant components use these numbers, so do not restrict them. Ill paste that value in the registry key.



Close out regedit and see now what BPA warns you about:
 The message now reads:

Some versions of MAPI clients are blocked on server SOLACESERVER.solace.local. Verify that version ‘6.x.x.x’ and version ‘8.x.x.x’ clients are not blocked as the Microsoft Exchange System Attendant process uses these version identifiers for performing server functions. Current MAPI blocking setting: 0.0.0-5.65535.65535;9.0.2711-11.65535.65535.

Thats correct then, as our warned numbers are excluded. Safely hide this message from all instances. If you have client connection problems, you can change this value in the future.