Sometimes crashes Access with Access Violation Exception (0xc0000005)

mTDHelper.bas、特に MagicalTDInitFunction から着手し、Class_Initialize が VBA7 64-bit 向けにそれを呼び出す方法を確認してください。Microsoft Access 2024 64-bit と提供された MsgBoxConfirm コードを使って、報告された Ribbon_OnClick のフローを再現し、ダイアログ操作を繰り返した場合の挙動を比較してください。間欠的なアクセス違反が切り分けられ、検証済みの修正または明確な制限が確立されれば完了です。

Hello,

First let me say that this is a very useful library to bring better dialogbox to users. Thank you for your hard work!

I would like to report a quite hard to grasp issue.

This is a Microsoft Access 2024 64 bits, in French, on Windows 11 Pro.
The TaskDialog library is latest (v1.6 R2).

Lately, I have been having regular Ms Access crash with an Access Violation Exception (0xc0000005) when doing various interaction (clicking on buttons, selecting a new line...).

The following event is logged in the Application log (somes parts in French):

Nom de l'application défaillante : MSACCESS.EXE, version : 16.0.17932.20602, horodatage : 0x690d8376
Nom du module défaillant : VBE7.DLL, version : 0.0.0.0, horodatage : 0x66c8d2d7
Exception code: 0xc0000005
Fault offset: 0x0000000000381e5a
Identifiant du processus défaillant : 0x51EC
Heure de début de l'application défaillante : 0x1DC6CE2C7798BE6
Chemin de l'application défaillante : C:\Program Files\Microsoft Office\Root\Office16\MSACCESS.EXE
Chemin du module défaillant : C:\Program Files\Common Files\Microsoft Shared\VBA\VBA7.1\VBE7.DLL
ID du rapport : 98df9afd-4af7-4584-9cb9-31323f331660
Nom complet du package défaillant : 
Package défaillant – ID d'application relatif : 

I was never able to find the issue as it is seemingly in random. If I try the exact same action after restarting the app, it works flawlessly.
The issue can also happen on different machine.
This is quite maddening.

However, this week I observed 3 random crashes happening on a specific button. It is a custom button added in the Ms Access Ribbon, and the first thing it does is displaying a confirmation dialog using this TaskDialog library.

When the crashes occurred, the dialog was never displayed. That's why I believe the issue may come from this library.

Here is the Sub in question :

Public Sub Ribbon_OnClick(Control As IRibbonControl)
    If MsgBoxConfirm("...") Then
        ' Do something
    End If
End Sub

And here are the support functions used:

Public Function MsgBoxConfirm(Content As Variant, Optional ContentTitle As Variant = "", Optional icon As TDICONS = IDI_QUESTION, Optional DefaultButton As TDRESULT = TD_YES) As Boolean
    Dim TaskDialog As New cTaskDialog
    With TaskDialog
        .Init
        .Flags = TDF_ENABLE_HYPERLINKS Or TDF_EXEC_HYPERLINKS Or TDF_SIZE_TO_CONTENT
        .title = "Title"
        .ParenthWnd = GetParenthWnd

        .MainInstruction = ContentTitle
        .Content = Content

        .CommonButtons = TDCBF_YES_BUTTON Or TDCBF_CANCEL_BUTTON
        .DefaultButton = DefaultButton

        .title = "Confirmation"
        .IconMain = icon

        .ShowDialog

        MsgBoxConfirm = .ResultMain = TD_YES
    End With
    Set TaskDialog = Nothing
End Function

Function GetParenthWnd() As LongPtr
    GetParenthWnd = Application.hWndAccessApp
    If Application.CurrentObjectType = acForm Then
        If IsFormDialog(Screen.ActiveForm) Then
            GetParenthWnd = Screen.ActiveForm.hwnd
        End If
    End If
End Function

Public Function IsFormDialog(frm As Form) As Boolean
    Dim hwnd As LongPtr
    Dim lngStyle As LongPtr
    hwnd = frm.hwnd
    lngStyle = GetWindowLong(hwnd, GWL_EXSTYLE)
    IsFormDialog = CBool((lngStyle And WS_EX_DLGMODALFRAME) = WS_EX_DLGMODALFRAME)
End Function

I don't remember having this kind of crashes when we used Access 2019 32 bits. Not on this button anyway.

I noticed this comment in the mTDHelper.bas file:

Public Sub MagicalTDInitFunction()
        'The trick is a GENIUS!
    'He identified the bug in VBA64 that had been causing the crashing.
    'As if by magic, calling this from Class_Initialize resolves the problem.
End Sub

I couldn't find any information on theses crashes (or how any real explanation of this "genius trick") but I though it may be related?

Thank you for your time and any help you can provide on this matter! 😸