QFileDialog::getOpenFileName causing program to crash

[JonB]

@BogdanPopa said in QFileDialog::getOpenFileName causing program to crash:

2 on_avast_dll_unload 0x7ffac8365310

Try disabling your Avast virus protector and see if it goes away?

[BogdanPopa]

@JonB I have also tried this and still no result

[JonB]

@BogdanPopa
Then I would expect you to be able to post a stack trace which does not show it dying in on_avast_dll_unload?

[crackysk]

I'm having similar issue as @BogdanPopa mentioned above.
Using QFileDialog::getSaveFileName instead of Open, but same concept...
Also, initial backtrace looked similar and contained avast detail, but managed to get past it and get a complete backtrace that has more sense...

1  ntdll!RtlCompareMemoryUlong                                                                   0x7ff8dab71aa0 
2  ntdll!RtlAllocateHeap                                                                         0x7ff8daafdd00 
3  ntdll!RtlAllocateHeap                                                                         0x7ff8daafb44d 
4  ntdll!RtlRegisterSecureMemoryCacheCallback                                                    0x7ff8dabc8c38 
5  ntdll!RtlAllocateHeap                                                                         0x7ff8daafd255 
6  ntdll!RtlAllocateHeap                                                                         0x7ff8daafb44d 
7  Windows.Storage!CFreeThreadedItemContainer_CreateInstance                                     0x7ff8d635ba26 
8  Windows.Storage!CFreeThreadedItemContainer_CreateInstance                                     0x7ff8d635b4be 
9  Windows.Storage!CCachedShellItem_CreateInstance                                               0x7ff8d635a3d2 
10 Windows.Storage!ILFindLastID                                                                  0x7ff8d636fc65 
11 Windows.Storage!SHCreateShellItemArrayFromIDLists                                             0x7ff8d640323f 
12 Windows.Storage!SHChangeNotification_Lock                                                     0x7ff8d6414537 
13 EXPLORERFRAME!DllGetClassObject                                                               0x7ff8a4a08a46 
14 EXPLORERFRAME!DllCanUnloadNow                                                                 0x7ff8a4a7d52a 
15 ??                                                                                            0x7ff8a4a01603 
16 ??                                                                                            0x7ff8a49ffa15 
17 EXPLORERFRAME!DllGetClassObject                                                               0x7ff8a4a3d680 
18 ??                                                                                            0x7ff8a49f873d 
19 ??                                                                                            0x7ff8a49f8551 
20 DefSubclassProc                                                                               0x7ff8bc959aba 
21 DSA_Create                                                                                    0x7ff8bc9598b7 
22 USER32!CallWindowProcW                                                                        0x7ff8d979e7e8 
23 USER32!DispatchMessageW                                                                       0x7ff8d979e229 
24 USER32!IsDialogMessageW                                                                       0x7ff8d979bfe0 
25 USER32!DialogBoxIndirectParamAorW                                                             0x7ff8d97bd8f6 
26 USER32!DialogBoxIndirectParamAorW                                                             0x7ff8d97bd5a1 
27 USER32!DialogBoxIndirectParamAorW                                                             0x7ff8d97bd452 
28 USER32!DialogBoxIndirectParamW                                                                0x7ff8d97bd3e8 
29 DllCanUnloadNow                                                                               0x7ff8d8c4617e 
30 GetFileTitleW                                                                                 0x7ff8d8c23064 
31 QWindowsNativeFileDialogBase::doExec                      qwindowsdialoghelpers.cpp      962  0x1e8480d9     
32 QWindowsNativeDialogBase::exec                            qwindowsdialoghelpers.cpp      183  0x1e937a97     
33 QWindowsDialogHelperBase<QPlatformFileDialogHelper>::exec qwindowsdialoghelpers.cpp      394  0x1e937a97     
34 QDialog::exec                                             qdialog.cpp                    553  0x67e6c699     
35 QFileDialog::getSaveFileUrl                               qfiledialog.cpp                2434 0x67e7efa6     
36 QFileDialog::getSaveFileName                              qfiledialog.cpp                2381 0x67e7f16b     
37 MainWindow::getDestination                                mainwindow.cpp                 288  0x4048ef       
38 MainWindow::qt_static_metacall                            moc_mainwindow.cpp             100  0x407be7       
39 QMetaObject::activate                                     qobject.cpp                    3778 0x1480c86      
40 QMetaObject::activate                                     qobject.cpp                    3631 0x1480fa4      
41 QAbstractButton::clicked                                  moc_qabstractbutton.cpp        312  0x67d70117     
42 QAbstractButtonPrivate::emitClicked                       qabstractbutton.cpp            414  0x67d70332     
43 QAbstractButtonPrivate::click                             qabstractbutton.cpp            407  0x67d718d0     
44 QAbstractButton::mouseReleaseEvent                        qabstractbutton.cpp            1011 0x67d71b71     
45 QWidget::event                                            qwidget.cpp                    8888 0x67cc9f42     
46 QAbstractButton::event                                    qabstractbutton.cpp            968  0x67d72d2c     
47 QPushButton::event                                        qpushbutton.cpp                684  0x67e013ec     
48 QApplicationPrivate::notify_helper                        qapplication.cpp               3752 0x67c8818e     
49 QApplication::notify                                      qapplication.cpp               3213 0x67c8f532     
50 QCoreApplication::notifyInternal2                         qcoreapplication.cpp           1061 0x14570a6      
51 QCoreApplication::sendSpontaneousEvent                    qcoreapplication.cpp           1463 0x14572ec      
52 QApplicationPrivate::sendMouseEvent                       qapplication.cpp               2699 0x67c8e8d6     
53 QWidgetWindow::handleMouseEvent                           qwidgetwindow.cpp              661  0x67cdf5f2     
54 QWidgetWindow::event                                      qwidgetwindow.cpp              281  0x67ce1a69     
55 QApplicationPrivate::notify_helper                        qapplication.cpp               3752 0x67c8818e     
56 QApplication::notify                                      qapplication.cpp               3109 0x67c8f253     
57 QCoreApplication::notifyInternal2                         qcoreapplication.cpp           1061 0x14570a6      
58 QCoreApplication::sendSpontaneousEvent                    qcoreapplication.cpp           1463 0x14572ec      
59 QGuiApplicationPrivate::processMouseEvent                 qguiapplication.cpp            2102 0xb31ed65      
60 QGuiApplicationPrivate::processWindowSystemEvent          qguiapplication.cpp            1837 0xb3201da      
61 QWindowSystemInterface::sendWindowSystemEvents            qwindowsysteminterface.cpp     1068 0xb303959      
62 QWindowsGuiEventDispatcher::sendPostedEvents              qwindowsguieventdispatcher.cpp 82   0x1e886ff9     
63 qt_internal_proc                                          qeventdispatcher_win.cpp       245  0x14abb5f      
64 USER32!CallWindowProcW                                                                        0x7ff8d979e7e8 
65 USER32!DispatchMessageW                                                                       0x7ff8d979e229 
66 QEventDispatcherWin32::processEvents                      qeventdispatcher_win.cpp       639  0x14ab2b9      
67 QWindowsGuiEventDispatcher::processEvents                 qwindowsguieventdispatcher.cpp 74   0x1e886fd7     
68 QEventLoop::processEvents                                 qeventloop.cpp                 138  0x14557c7      
69 QEventLoop::exec                                          qeventloop.cpp                 225  0x1455be5      
70 QCoreApplication::exec                                    qcoreapplication.cpp           1364 0x145e86e      
71 QGuiApplication::exec                                     qguiapplication.cpp            1779 0xb315d9d      
72 QApplication::exec                                        qapplication.cpp               2909 0x67c88070     
73 qMain                                                     main.cpp                       10   0x4015c3       
74 WinMain                                                   qtmain_win.cpp                 104  0x409cd2       
75 __tmainCRTStartup                                                                             0x4013c7       
76 WinMainCRTStartup                                                                             0x4014cb

Sorry if formatting of backtrace is not ideal...

Also, maybe relevant note, this issue happened on multiple machines (a friend of mine is using application that I provided via installer and reported me an issue and it fails in same manner on both of our machines).
Since application has been working for years (3 more precisely) before this without any issues, my guess would be that some kind of Windows (also using Win10) update messed something up, but can't be sure about it.

I'm currently trying to use newer version of Qt (one I was using is fairly old, 5.12.0) hoping that one with more recent date would include some kind of fix for this, but according to this problem report I don't feel so confident about it. :)

Posting this in case it helps someone else.

[JonB]

@crackysk said in QFileDialog::getOpenFileName causing program to crash:

Since application has been working for years (3 more precisely) before this without any issues, my guess would be that some kind of Windows (also using Win10) update messed something up, but can't be sure about it.

It is highly likely this is the case, sadly. I don't know what you can do about it (sometimes it's possible the next patch/update corrects an issue), but you might verify:

• I think it's clear the error comes when using the native Windows Save File dialog. Try passing QFileDialog::DontUseNativeDialog? But I'm not sure that works with getSaveFileName(), you may also have to try...
• ... Use a QFileDialog instance and setAcceptMode(QFileDialog::AcceptSave) to try your own code instead of the inbuilt static QFileDialog::getSaveFileName().

At least you will know what is required to reproduce the issue.

[crackysk]

@JonB
I've tried first option before posting yesterday, but forgot to mention it (knew I would forget something).
Today I tried the approach with using QFileDialog instance and still have same issue.

One interesting thing is that with QFileDialog::DontUseNativeDialog set to false application works "slightly better". Let me try to elaborate:

• When set to false, Windows dialog opens fully, shows a content of starting location folder, but then freezes and runs send problem report mechanism
• When set to true, something I believe should be Qt dialog opens, but dialog is fully white without any useful information and instantly runs send problem report mechanism

Will try to play further with it and see if I can make it work somehow.
Thank you for your replies and time.

[LaCucaracha]

I've had the same issue in the last few days and managed to get around it.

I've had the same backtrace as shown above. On an app that worked for years. Qt 5.9 and now 5.15. Windows 10.

I don't use a QFileDialog but a QFileSystemModel set into a QTreeView.
When there is nothing to display, there is no crash (TreeView hidden, Model not set or Rootpath and Filters set to display an empty location).

My solution was to remove the icons from the display by overriding the function data() of QFileSystemModel to ignore the Qt::DecorationRole :

QVariant MyCustomFileModel::data(const QModelIndex& index, int role) const
{
    if (role == Qt::DecorationRole)
        return QVariant();
    else
        return QFileSystemModel::data(index, role);
}

No icons. But it works.

Digging further, i made my own QFileIconProvider to give to the model.
The function icon is the issue.

QIcon QFileIconProvider::icon(const QFileInfo &info) const

If i override it to return QIcon() it works fine, with icons. They might be different from what they were before and there might be some missing ones but i'm not sure. Probably has to do with the style of the application. (No custom style applied here)

For the next step, looking into QFileIconProviderPrivate, QGuiApplicationPrivate and QPlatformTheme might be a bit too much for my skills.

Also, the options QFileIconProvider::DontUseCustomDirectoryIcons and all of the QFileSystemModel options (DontWatchForChanges, DontResolveSymlinks, DontUseCustomDirectoryIcons) do not change anything.

[crackysk]

@LaCucaracha

Thank you for reply. I even tried QFileIconProvider::DontUseCustomDirectoryIcons at some point, but didn't cross my mind that's not doing anything useful.

I tried providing icon provider directly to static QFileDialog for save/open file that I was using, but it made no difference. Also, creating custom FileIconProvider and providing it to instance of QFileDialog created in app made no difference (also creating custom QFileDialog class).
So, I basically moved to same thing as you did. I've written my own dialog that's doing same thing as static one I was using before.
Now, I have treeView and listView next to each other, both of them provided with different QFileSystemModel (different when it comes to filter) and provided custom QFileIconProvider class that has icon() overridden. And really, crashes are gone!

Honestly, I don't even mind having same file icon for each file type. For purposes I need it for, this is more than enough. But, if someone needs it, probably can even do similar thing like you did for a role and look for a specific QFileInfo that makes a mess and for all others use just default constructor for QIcon as you did.

All that's left to do is handling cosmetics in order to make this new QDialog as close as possible to the one.

[Vsevolod7]

Same problem.

[A Former User]

I copy your codes and run it on win11 successfully. I used Qt5.13 and the compiler 'MingGW 64bit'. Add I tried the compiler 'MSVC2015', it is all right too. I think our developing environment are similar to each other.

[az1699]

Same issue here. I've a test application made few months ago that always worked. I fixed by working around using DontUseNativeDialog.

If I run the same application, same build, on windows sand box it works perfectlly. Dont know why, windows sand box should have the same windows system update as my system

[az1699]

I also tried this, don't why but after istancing QFileDialog with QFileDialog::DontUseNativeDialog I can start using QFileDialog in the previous way. I tested this simple example and works.

    static bool first_run = true;
    if (first_run) {
        CmdOpenFile(QFileDialog::getOpenFileName(0, "Open some file", QString(), QObject::tr("All files (*.*)"), nullptr, QFileDialog::DontUseNativeDialog));
        first_run = false;
    } else {
        CmdOpenFile(QFileDialog::getOpenFileName(0, "Open some file", QString(), QObject::tr("All files (*.*)")));
    }

[Violet Giraffe]

I can't speak for every case in particular, but these symptoms are very typical for a misbehaving shell / Explorer extension, and not related to Qt, most likely.

I've seen some projects (for example - Firefox) maintain a list of known faulty DLLs and use LoadLibrary hooks to prevent those DLLs from loading.

[sir_clive]

I'd like to add my experience with this issue.

I pulled my hair out over a very similar (probably the same?) problem lately, and it turned out that AVAST and AVG (practically the same product) are causing this problem in my case. These programs must be uninstalled (not deactivated, but completely uninstalled) for my program to start working again.

My program was working on multiple versions of Windows for years already, with no issues whatsoever. The problems started in February this year (2023), and affect every single "file dialog" instance my program tries to open.

The tip with not using native dialog did not help in my case. Also VMWare based Windows installations are not affected, only the "bare metal" ones. Also, 5.x and 6.x QT versions are both crashing if AVAST or AVG are installed.

I'm surprised not more QT programs are affected, this is the best thread I found so far.

[az1699]

@sir_clive I've Avast antivurs on my computer, i tested in an other without avast and works :(

So maybe reporting this issue the could fix it

[VirtualFloat]

Running into the same issue here on some corporate windows 11 machines. So in 2025 it is still causing issues.

[Violet Giraffe]

@VirtualFloat
Does the crash occur in a Qt .dll, or inside a foreign dll injected by some security software? The latter is, unfortunately, not uncommon.