PRB: MTS Event Log 4098 "Unexpected Object Reference Count" (259463)

SYMPTOMS

Microsoft Transaction Server (MTS) may log the following informational event:

Unexpected object reference count. The object still had references after the run-time environment released its last reference. Unbind
(Package: PSLk108 OSEP) (ProgId: Project.Class) (CLSID: {EA6CD25E-2B12-11D3-8F30-0001FA328EF7}) (Interface: IUnknown) (IID: {00000000-0000-0000-C000-000000000046}) (Method: 2) (Microsoft Transaction Server Internals Information: File: d:\viper\src\runtime\context\ccontext.cpp, Line: 2807)

CAUSE

This log indicates that an object did not return 0 (zero) from the IUnknown::Release method when the MTS context wrapper was releasing it. This informational message indicates the possibility of a leak.

There are two possible reasons for this log:

Someone called AddRef on your component without releasing it. This may have been done without the context wrapper. As a result, an instance is left (hanging around--colloquial) in memory, which most likely contributes to a memory leak for the process. To fix this problem, you must find the offending code and correct it.
The component is not returning 0 (zero) from IUnknown. The object is released when it has a reference count of 0. The COM specification does not require this, and some tools (such as PowerBuilder) do not return 0 from the last Release.

In this case, to stop the event log, you must wrap the objects in other components (such as Microsoft Visual Basic components) that return 0 from the Release call. The wrapping components must be installed in MTS, and the wrapped components, which must not be installed in MTS, must reside in the same apartment as the wrapping component.

MORE INFORMATION

Steps to Reproduce Behavior

In Visual Basic, create an ActiveX dynamic-link library (DLL). Name the project "MyRefcount" and the class "CMyRefcount".
Add a reference to Microsoft Transaction Server Type library.

Add the following code to CMyRefcount:

Public Function GetMe() As Object
    Dim context As ObjectContext

    Set context  = GetObjectContext

    Set GetMeToo = Me 'should be SafeRef(Me)
    
    context.SetComplete
End Function

Build MyRefcount. Under the Component tab of the Project Properties dialog box, click Binary compatibility in the Version Compatibility list. Add MyRefcount to a new MTS package.
Create a Visual Basic Standard EXE.
Add a reference to the MyRefcount project.

Add a button to the form, and paste the following code in the handler:

Private Sub Command1_Click()
    Dim c As MyRefcount.CMyRefcount
    Dim c1 As MyRefcount.CMyRefcount
    
    Set c = CreateObject("MyRefcount.CMyRefcount")
    
    Set c1 = c.GetMe
End Sub

Compile and run the executable file. The above-mentioned message appears in the event log. This informational message appears only in MTS and not in COM+.