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[SOLVED] Qt Creator: "This application failed to start because it could not find or load the Qt platform plugin "windows"

  • I' have installed Qt 5.2.0 MSVC, VS 2012 and QtVsAddin 1.2.2 The problem is that after installation, everything works fine for example 5 days. That's mean that I could easily run and build applications either in Qt Creator or Visual Studio. But then I can't build my app's that using Qt, and cann't execute Qt creator. When I try to build project in VS it write to console: moc: Cannot create .\GeneratedFiles\Debug\moc_myapp.cpp also when I want run Qt Creator it's output :
    This application failed to start because it could not find or load the Qt platform plugin "windows"
    However, all my builded apps executes properly. Reinstallation of Qt remove this problem for some time, but I'm tired every week reinstall Qt. What could cause this?

  • Hi, I were to guess I'd say this sounds like you have an antivirus program that isn't fond of QtCreator :-(

    (If Qtcreator fails to start with that plugin error, most likely it's because the qt.conf file in ..\Tools\QtCreator\bin has been kidnapped/quarantined.)

  • I don't have antivirus :) In ..\Tools\QtCreator\bin there is qt.conf and looks as follow:

  • Hmmm, but today QtCreator works for you? So maybe wait for it to fail again, then check qt.conf...

  • No, right now it's not working. I all time try find reason what's make it crash, but unsuccessful.

  • I see, interesting! First do a chkdsk just to make sure your hard disk is ok, then you can try to trace how/where QtCreator fails:

    Download "Dependency Walker":
    Start it and open qtcreator.exe in ..\Tools\QtCreator\bin
    Then under Profile select Start Profiling (just click Ok when the Profile Module dialog box is shown)

  • This is chkdsk log:
    This is Dependency Walker log:

  • Hi, according to Dependency Walker's log it seems you have "WinPatrol": installed, try to uninstall it, reboot and see if QtCreator works better...

  • Just 3 minutes ago, I reinstalled Qt, that's why I must wait about week to see if it problem because of WinPatrol or something other.

  • No problem, maybe I hear from you next week :-)

  • The problem isn't in WinPatrol because I uninstalled it, but problem appeared again, today. However yesterday everything worked fine. But now again appeared moc errors in VS 2012 and Qt Creator don't start. Also I noticed that when I click on Qt Project and Qt Settings in QT5 Tab in Visual Studion, it opens console for a second. It turned out that it was qmake.exe executed from C:\Users\Admin\AppData\Local\Temp\3582-490 folder also there were moc.exe, qtcreator.exe, rcc.exe. When I deleted them from folder, they appeared again when I started to build project and run QtCreator.

  • Well, after some analisis I found that all exe files that I execute from Qt folders, automatically are copied to : C:\Users\Admin\AppData\Local\Temp\3582-490 But when I reinstalled Qt, they stopped copying. I think that there is virus on my PC.

  • Maybe not a virus, but something called "Microsoft Detours":

    It seems to be package for instrumentation/tracing. Perhaps something in your PC triggers it after 5 days, then it rewrites/copies the .exe files to C:\Users\Admin\AppData\Local\Temp\3582-490.
    (And that's why QtCreator cannot find its qt.conf, which it needs to start properly.)

    Not 100% sure, but see if you can find it and uninstall it...

  • Well, I think that problem is solved, because after uninstallation all software that can do something that I described in topic, QtCreator now executes without errors.

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