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This application failed to start because it could not find or load the Qt platform plugin "windows" in "".

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qt creatorqt installationqwebengine
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  • A Offline
    A Offline
    allenck
    wrote on last edited by
    #1

    After using the maintenance tool to download QT version 5.6 in addition to version 5.7 I started getting the error that it could not find the Qt platform "Windows". Before this, I was able to compile and run under 5.7 without this error but now it occurs there as well.

    Figuring something was wrong with the Qt installation, I completely uninstalled all instances of Qt and reinstalled 5.6 and 5.7. Same problem.

    After researching the problem, I tried adding the define for QT_PLUGIN_PATH to the projects defines. This solved the problem of loading the platform "windows" plugin but now complained: "Could not find QtWebEngineProcess.exe". I added another define QTWEBENGINEPROCESS_PATH and was able to start the app. However, the QWebEngine widget doesn't display anything. However a series of debug messages may explain why:
    Qt WebEngine ICU data not found at C:/Projects/mapper_QT/mapper/mapper_app/debug. Trying fallback directory... The application MAY NOT work.
    Installed Qt WebEngine locales directory not found at location C:/Projects/mapper_QT/mapper/mapper_app/debug/translations\qtwebengine_locales. Trying application directory...
    Qt WebEngine locales directory not found at location C:/Projects/mapper_QT/mapper/mapper_app/debug\qtwebengine_locales. Trying fallback directory... Translations MAY NOT not be correct.
    Qt WebEngine resources not found at C:/Projects/mapper_QT/mapper/mapper_app/debug/resources. Trying parent directory...
    Qt WebEngine resources not found at C:/Projects/mapper_QT/mapper/mapper_app/debug. Trying application directory...
    Qt WebEngine resources not found at C:/Projects/mapper_QT/mapper/mapper_app/debug. Trying fallback directory... The application MAY NOT work.

    The same source compiled on another PC with5.6 works fine. My conclusion is that there is something wrong with my QT installation; probably related to qtcreator.conf files.

    I might point out that in both cases, I am running under Windows 7 and using the MSVC2013 distribution. I have not recompiled any part of QT except the SQLite plugin.

    The version of QtCreator that was downloaded is 4.0.3. However the same problem occurs with an older copy of QtCreator (3.0.1) that I had on my machine

    Should I delete all the QtCreator.conf files or is there something in the registry that is causing QtCreator to not work properly?

    Allen Kempe

    raven-worxR 1 Reply Last reply
    0
    • A allenck

      After using the maintenance tool to download QT version 5.6 in addition to version 5.7 I started getting the error that it could not find the Qt platform "Windows". Before this, I was able to compile and run under 5.7 without this error but now it occurs there as well.

      Figuring something was wrong with the Qt installation, I completely uninstalled all instances of Qt and reinstalled 5.6 and 5.7. Same problem.

      After researching the problem, I tried adding the define for QT_PLUGIN_PATH to the projects defines. This solved the problem of loading the platform "windows" plugin but now complained: "Could not find QtWebEngineProcess.exe". I added another define QTWEBENGINEPROCESS_PATH and was able to start the app. However, the QWebEngine widget doesn't display anything. However a series of debug messages may explain why:
      Qt WebEngine ICU data not found at C:/Projects/mapper_QT/mapper/mapper_app/debug. Trying fallback directory... The application MAY NOT work.
      Installed Qt WebEngine locales directory not found at location C:/Projects/mapper_QT/mapper/mapper_app/debug/translations\qtwebengine_locales. Trying application directory...
      Qt WebEngine locales directory not found at location C:/Projects/mapper_QT/mapper/mapper_app/debug\qtwebengine_locales. Trying fallback directory... Translations MAY NOT not be correct.
      Qt WebEngine resources not found at C:/Projects/mapper_QT/mapper/mapper_app/debug/resources. Trying parent directory...
      Qt WebEngine resources not found at C:/Projects/mapper_QT/mapper/mapper_app/debug. Trying application directory...
      Qt WebEngine resources not found at C:/Projects/mapper_QT/mapper/mapper_app/debug. Trying fallback directory... The application MAY NOT work.

      The same source compiled on another PC with5.6 works fine. My conclusion is that there is something wrong with my QT installation; probably related to qtcreator.conf files.

      I might point out that in both cases, I am running under Windows 7 and using the MSVC2013 distribution. I have not recompiled any part of QT except the SQLite plugin.

      The version of QtCreator that was downloaded is 4.0.3. However the same problem occurs with an older copy of QtCreator (3.0.1) that I had on my machine

      Should I delete all the QtCreator.conf files or is there something in the registry that is causing QtCreator to not work properly?

      raven-worxR Offline
      raven-worxR Offline
      raven-worx
      Moderators
      wrote on last edited by
      #2

      @allenck
      this question has been asked a million times already. please use the search.

      --- SUPPORT REQUESTS VIA CHAT WILL BE IGNORED ---
      If you have a question please use the forum so others can benefit from the solution in the future

      A 1 Reply Last reply
      0
      • raven-worxR raven-worx

        @allenck
        this question has been asked a million times already. please use the search.

        A Offline
        A Offline
        allenck
        wrote on last edited by
        #3

        @raven-worx Perhaps you could provide a link to the solution. I have found numerous posts on this subject however none of them come close to providing a solution. For one thing, most of them are about trying to **deploy **an application. That is not the case here. I am trying to run an application in QtCreator compiled on a clean download of QT. Furthermore, I had no problems until I used the QT maintenance tool to add Qt5.6 to an already existing download of QT5.7. The real question is how can I download a copy of QT that is usable.

        Allen Kempe

        mrjjM 1 Reply Last reply
        0
        • A allenck

          @raven-worx Perhaps you could provide a link to the solution. I have found numerous posts on this subject however none of them come close to providing a solution. For one thing, most of them are about trying to **deploy **an application. That is not the case here. I am trying to run an application in QtCreator compiled on a clean download of QT. Furthermore, I had no problems until I used the QT maintenance tool to add Qt5.6 to an already existing download of QT5.7. The real question is how can I download a copy of QT that is usable.

          mrjjM Offline
          mrjjM Offline
          mrjj
          Lifetime Qt Champion
          wrote on last edited by mrjj
          #4

          @allenck
          Hi
          That sounds very strange. (since its in creator)
          You could try the offline installer for vs2013
          https://www.qt.io/download-open-source/#section-2
          Qt 5.7.0 for Windows 64-bit (VS 2013, 904 MB) (info)
          Qt 5.7.0 for Windows 32-bit (VS 2013, 909 MB) (info)
          OR
          Qt 5.6.1-1 for Windows 64-bit (VS 2013, 829 MB) (info)
          Qt 5.6.1-1 for Windows 32-bit (VS 2013, 833 MB) (info)
          Maybe install to new folder c:\myQt

          I have only had such issues once and it turn out to be Avast virus scanner that
          silently ate some files :)

          I agree that something is funky with your installation. Im not aware of any registry items
          that would make it fail like that.
          If you make plain new GUI app, can it work?
          Its just QWebEngine project that gives errors?

          1 Reply Last reply
          1
          • A Offline
            A Offline
            allenck
            wrote on last edited by
            #5

            thanks. I found a file called qt.conf in my debug directory. I deleted it and now everything is OK. I vaguely recall downloading such a file when following another post. Anyway it seems to have been the problem so I guess the issue is solved.

            Allen Kempe

            mrjjM 1 Reply Last reply
            1
            • A allenck

              thanks. I found a file called qt.conf in my debug directory. I deleted it and now everything is OK. I vaguely recall downloading such a file when following another post. Anyway it seems to have been the problem so I guess the issue is solved.

              mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by
              #6

              @allenck
              ahh, yes that would do it.
              It can tell Qt to look from plugins in other places.
              http://doc.qt.io/qt-5/qt-conf.html

              Good catch :)

              1 Reply Last reply
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