SNA Windows 3.x Client Displays Warning 956, Won't Unload

ID: Q235723

The information in this article applies to:

Microsoft SNA Server, versions 4.0, 4.0SP1, 4.0SP2, 4.0SP3

SYMPTOMS

After running one or more 16-bit Windows APPC applications on top of the SNA Windows 3.x client (on a Windows 95 workstation), the Wnap.exe process may display the following error message even though all SNA client applications have ended:

SNA Server Messager

SNA Server Warning 956
SNA Base cannot be terminated while its services are being used.

This problem couldn't be reproduced when running the SNA Windows 3.x client on Windows NT. Traces reveal that the APPC applications are not calling WinAPPCCleanup prior to termination, contributing to the problem.

CAUSE

If an APPC application fails to call WinAPPCCleanup before the process terminates, the SNA Windows 3.x client software relies on the operating system to notify Wnap.exe that the Win16 process has ended. However, when running on Windows 95, this was not occurring properly.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp

The English version of this fix should have the following file attributes or later:

File name	Date	Time
Wnap.exe	05/20/99	12:06p

NOTE: Because of file dependencies, the most recent fix that contains the above files may also contain additional files.

WORKAROUND

For all APPC applications, ensure that they properly call WinAPPCStartup when the APPC process first starts, and WinAPPCCleanup before the process ends.

STATUS

Microsoft has confirmed this to be a problem in Microsoft SNA Server version 4.0.

Additional query words:

Keywords : sna4 sna4sp1 sna4sp2 sna4sp3
Version : WINDOWS:4.0,4.0SP1,4.0SP2,4.0SP3
Platform : WINDOWS
Issue type : kbbug