On machines with the DEC Alpha architecture, the stub supports additional functionality as follows:
Preferentially loads DLLs from the System32 directory for native Alpha applications, and DLLs from the Sys32x86 directory for x86 applications.
Handles simple and extended MAPI cross-architecture calls in both directions if a DLL for a particular architecture is not present. That is, x86 simple MAPI calls can resolve to Alpha MAPI DLLs and vice versa.
Running Fixmapi.exe
Using the Mapi32stub.dll, Fixmapi.exe installs Mapi32.dll in both the System32 and Sys32x86 directories. You must rerun this executable after installing or uninstalling any email client to restore the stub libraries. Note that, as described in the previous section, these MAPI stub libraries dispatch MAPI calls and resolve cross-architecture MAPI calls between x86 and Alpha architectures.
Unsupported Configurations
Running the native Alpha Exchange client and the x86 version of Microsoft Outlook is not supported. If both are installed, Outlook crashes when messages are sent, and Send on the File menu does not work correctly for x86 applications (although the application does not crash.)
Exchange Client and Outlook Workaround
If you would like to have both the Exchange client and Outlook installed on the same machine, you need to install the x86 version of the Exchange client. When the x86 version of Outlook is installed, the x86 version of the Exchange client is installed at the location %SYSTEMDRIVE%\Program Files(x86)\Windows Messaging\ExChng32.exe.
To Uninstall the native Exchange Client
Run the Exchange setup program and ensure that all shared components are removed. These include the Windows Messaging and VBScript components.
Manually delete the %SYSTEMROOT%\system32\Mapi32x.dll if it exists.
Re-install Outlook if it was previously installed.
Run the Fixmapi.exe executable from the command prompt:
c:>fixmapi.exe
To Uninstall Outlook
Run the Outlook setup program and remove Windows Messaging.
Manually delete the file %SYSTEMROOT%\sys32x86\Mapi32x.dll if it exists.
If the native Exchange client was previously installed, you must now reinstall it.
Run the fixmapi.exe executable from the command prompt:
c:>fixmapi.exe
To Make the Native Exchange Client Your Default Mail Client
You can do this in two ways:
In Internet Explorer, click Internet Options on the View menu and select the Exchange client on the Programs tab.
Set the HKLM\Software\Clients\Mail::(default) registry value to the Microsoft Exchange subkey. The Microsoft Exchange subkey is not created when the Exchange client is installed, so you need to do so manually.