Knowledge base KB0169

Conflict with another add-in: Subclassing error in Excel


When I open or close Excel, I receive one of the following error messages:

  • CRITICALWITHMSG library\ui\win\safesubclassimpl.cpp(392): APIERR 1400 Invalid window handle.
  • CRITICAL library\ui\dpi_win.cpp(80): _ASSERTEQUAL(IsWindow(wnd), TRUE): IsWindow(wnd)=0, TRUE=1
  • CRITICAL library\ui\win\safesubclassimpl.cpp(239): _ASSERT(0!=lResult)
  • CRITICAL library\objecttypes\obj.cpp(40): _ASSERTEQUAL(m_nRefCnt, (unsigned int)INSIDE_DESTRUCTOR_OFFSET): m_nRefCnt=1073741825, (unsigned int)INSIDE_DESTRUCTOR_OFFSET=1073741824
  • CRITICAL library\ui\win\safesubclassimpl.cpp(318): _ASSERTPRINT(pprobe->bSetWindowProcUnicode==bCallWindowProcUnicode || IsStubWndProc(pwndprocModifiedCall)): SetWindowLongPtr: 0x24E94D64; CallWindowProc: 0x22219522


Such errors in think-cell are caused by a programming error in another add-in. Our developers analyzed the issue in detail. According to our analysis, hooking/unhooking issues cause this problem when multiple add-ins are available.

A hook is a mechanism by which a function can intercept events before they reach an application. The function can act on events and, in some cases, modify or discard them. For further details, please see KB0201.

Solutions and known issues

The following add-ins were identified to cause this issue:

  • SAP BusinessObjects Analysis (AO)
    The problem was fixed in SAP AO version 2.8 SP4 and later after we reported it to SAP for SAP BusinessObjects Analysis (see SAP ticket 557711 / 2018).
  • Boldon James Classifier
    The problem was fixed in version 3.14.3 and later.
  • Adaptive Insights (now Workday Adaptive Planning) OfficeConnect
    We were in contact with the Adaptive Insights / Workday Adaptive Planning support team. We are not yet aware of a fix. Therefore, please try if the issue continues to occur with the latest OfficeConnect version. If yes, and you want to ask for a fix, you may contact your Workday Adaptive Planning support and refer to help desk request: #208737: OfficeConnect Add-in compatibility issue with think-cell.
  • SAP Business Explorer Analyzer
    This problem was originally reported for SAP Business Explorer (see SAP ticket 1019869/2011). It was confirmed by SAP, but they decided not to fix it as BEx was only in maintenance mode and no major changes could be made.

    Users recently (in 2021) reported the following error when opening Excel using the SAP BEx Analyzer shortcut and opening a database afterwards:

    CRITICAL library\ui\win\safesubclassimpl.cpp(318): _ASSERTPRINT(pprobe->bSetWindowProcUnicode==bCallWindowProcUnicode || IsStubWndProc(pwndprocModifiedCall)): SetWindowLongPtr: 0x24E94D64; CallWindowProc: 0x22219522

    So far there are no changes. There is still no solution available. SAP recommends switching to SAP BusinessObjects Analysis, which already contains a fix (see above).

  • Microsoft Azure Information Protection (AIP) and S&P Capital IQ
    Please refer to our knowledge base article KB0237.


You can find the list of active add-ins in the Excel/PowerPoint Options: File > Options>Add-ins.

To find out which add-in(s) may be involved in your case, temporarily deactivate other add-ins as explained in KB0091: How can I find out which add-in causes a problem?

Contact support

In case you are not using any of the mentioned add-ins, please contact our support team and provide the following information:

  • A description of the last steps you did before the error occurred.
  • A screenshot showing your add-ins in Excel (or PowerPoint in case the error occurs with PowerPoint): File > Options > Add-ins.
  • The think-cell log files by clicking on Request Support in the think-cell error message.