Error 26 or "MAPI_E_NOT_SUPPORTED" with MAPI-Based Program

• Microsoft Windows 95
• Microsoft Windows 95 OEM Service Release versions 2, 2.1, 2.5
• Microsoft Internet Explorer versions 4.0, 4.01 for Windows 95

SYMPTOMS

When you run a Messaging Application Programming Interface-based (MAPI- based) program in Windows 95, you may receive error number 26 or the error message "MAPI_E_NOT_SUPPORTED."

CAUSE

This behavior can occur after you install Internet Explorer 4.0 or 4.01 or the Microsoft Distributed COM Update for Windows 95 (DCOM95), or if you are using a non-English version of Windows 95 OEM Service Release 2 (OSR2) or later.

Earlier versions of the Windows Messaging System (WMS) Mapisrvr.exe file do not support the COM call to the CoCreateInstance() function properly and return the E_NOINTERFACE value.

NOTE: Because this problem does not occur in Windows 95 with the original WMS until you install DCOM95 or Internet Explorer 4.0 or 4.01, the problem may seem to be caused by either DCOM95 or Internet Explorer. The problem actually occurs because the earlier Mapisrvr.exe file does not properly support calls to the CoCreateInstance() function.

RESOLUTION

For English-language versions of Windows 95, you can resolve this problem by installing the latest WMS for Windows 95. The latest WMS is available from the following Microsoft Web site:

   http://www.microsoft.com/windows95/info/exupd.htm

STATUS

Microsoft has confirmed this to be a problem with the earlier Mapisrvr.exe file included with the original Windows 95 distribution. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.