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This application failed to start because no Qt platform ...

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #3

    Hi,

    Since you are starting your application from the explorer and from the look of the content of the folder, that's because you didn't deploy your application properly. You are missing the plugins directory.

    Use windeployqt to deploy your application.

    Interested in AI ? www.idiap.ch
    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
    2
    • JKSHJ JKSH

      You must put qwindows.dll inside a subfolder: platforms\qwindows.dll

      Better yet, use the windeployqt tool: https://doc.qt.io/qt-5/windows-deployment.html

      @tomy said in This application failed to start because no Qt platform ...:

      And I guess it's related to my Environment Variables Path, but there isn't any path of Qt there:

      That is not a problem. In fact, Qt should not be in your PATH.

      tomyT Offline
      tomyT Offline
      tomy
      wrote on last edited by tomy
      #4

      @JKSH , @SGaist
      Hi,

      You must put qwindows.dll inside a subfolder: platforms\qwindows.dll

      I did this, and now no error messages. And nothing is shown when executing the file!

      As for windeployqt, for the time being I like not to use it and run the program without it.

      And what's the recommended directory to copy the .dll files from and paste them inside the executable folder, please?

      mrjjM 1 Reply Last reply
      0
      • tomyT tomy

        @JKSH , @SGaist
        Hi,

        You must put qwindows.dll inside a subfolder: platforms\qwindows.dll

        I did this, and now no error messages. And nothing is shown when executing the file!

        As for windeployqt, for the time being I like not to use it and run the program without it.

        And what's the recommended directory to copy the .dll files from and paste them inside the executable folder, please?

        mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by mrjj
        #5

        @tomy said in This application failed to start because no Qt platform ...:

        As for windeployqt, for the time being I like not to use it

        But its for gathering the needed DLLS ?
        its nothing more than a copy helper.
        So why on earth not use it?

        Anyway, i like this site for info what minimum structure of the folder
        http://www.tripleboot.org/?p=138

        You would copy from the compilers folder under Qt.
        "C:\Qt\5.12.0\mingw73_64\bin"

        tomyT 1 Reply Last reply
        3
        • mrjjM mrjj

          @tomy said in This application failed to start because no Qt platform ...:

          As for windeployqt, for the time being I like not to use it

          But its for gathering the needed DLLS ?
          its nothing more than a copy helper.
          So why on earth not use it?

          Anyway, i like this site for info what minimum structure of the folder
          http://www.tripleboot.org/?p=138

          You would copy from the compilers folder under Qt.
          "C:\Qt\5.12.0\mingw73_64\bin"

          tomyT Offline
          tomyT Offline
          tomy
          wrote on last edited by
          #6

          @mrjj
          Hi mrjj,
          Thanks. Your post solved the issue. :)

          mrjjM 1 Reply Last reply
          0
          • tomyT tomy

            @mrjj
            Hi mrjj,
            Thanks. Your post solved the issue. :)

            mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by
            #7

            @tomy
            Super.
            One note.
            There is 2 version in the folder.
            Like qt5Core
            and
            qt5CoreD
            the D is the debug version.
            Make sure to always compile in release mode ( your app)
            and only copy the non D version to your folder.

            tomyT 1 Reply Last reply
            2
            • mrjjM mrjj

              @tomy
              Super.
              One note.
              There is 2 version in the folder.
              Like qt5Core
              and
              qt5CoreD
              the D is the debug version.
              Make sure to always compile in release mode ( your app)
              and only copy the non D version to your folder.

              tomyT Offline
              tomyT Offline
              tomy
              wrote on last edited by
              #8

              @mrjj
              Yeah, I knew these, but still thanks. :)

              1 Reply Last reply
              1
              • C Offline
                C Offline
                crush
                wrote on last edited by
                #9
                This post is deleted!
                1 Reply Last reply
                0
                • JKSHJ JKSH

                  You must put qwindows.dll inside a subfolder: platforms\qwindows.dll

                  Better yet, use the windeployqt tool: https://doc.qt.io/qt-5/windows-deployment.html

                  @tomy said in This application failed to start because no Qt platform ...:

                  And I guess it's related to my Environment Variables Path, but there isn't any path of Qt there:

                  That is not a problem. In fact, Qt should not be in your PATH.

                  C Offline
                  C Offline
                  crush
                  wrote on last edited by
                  #10

                  @JKSH hi,i did what you said,but still have the same problem.Can you tell me how to solve it,please?

                  mrjjM 1 Reply Last reply
                  0
                  • C crush

                    @JKSH hi,i did what you said,but still have the same problem.Can you tell me how to solve it,please?

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by
                    #11

                    @crush
                    hi
                    did you use the windeployqt tool ?

                    C 1 Reply Last reply
                    0
                    • mrjjM mrjj

                      @crush
                      hi
                      did you use the windeployqt tool ?

                      C Offline
                      C Offline
                      crush
                      wrote on last edited by
                      #12

                      @mrjj not yet because i don't know how to use it

                      1 Reply Last reply
                      0
                      • SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on last edited by
                        #13

                        @crush It's explained in the documentation.

                        Interested in AI ? www.idiap.ch
                        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                        1 Reply Last reply
                        3
                        • C Offline
                          C Offline
                          Chris King
                          wrote on last edited by
                          #14

                          I am running into this message attempting to run Houdini. If I google this error message I find talk of many people running into this issue when running various apps. Autodesk Maya, Google One drive to name a few. Are all these vendors not properly installing their apps? Are users expected to modify their installations of these apps using windeployqt?

                          mrjjM JKSHJ 2 Replies Last reply
                          0
                          • C Chris King

                            I am running into this message attempting to run Houdini. If I google this error message I find talk of many people running into this issue when running various apps. Autodesk Maya, Google One drive to name a few. Are all these vendors not properly installing their apps? Are users expected to modify their installations of these apps using windeployqt?

                            mrjjM Offline
                            mrjjM Offline
                            mrjj
                            Lifetime Qt Champion
                            wrote on last edited by
                            #15

                            @Chris-King
                            Hi
                            Make sure you are using a fully patch supported windows version. Win 7 might give issues.
                            It might not always be the vendors fault but some other installed app that added its folder to the global search path.
                            No, windeployqt is meant for the developers, not end user as for it to function, you need a Qt installation to get the
                            DLLs from. Besides the end user would have to know which compiler and Qt version that was used.

                            1 Reply Last reply
                            2
                            • C Chris King

                              I am running into this message attempting to run Houdini. If I google this error message I find talk of many people running into this issue when running various apps. Autodesk Maya, Google One drive to name a few. Are all these vendors not properly installing their apps? Are users expected to modify their installations of these apps using windeployqt?

                              JKSHJ Offline
                              JKSHJ Offline
                              JKSH
                              Moderators
                              wrote on last edited by
                              #16

                              @Chris-King said in This application failed to start because no Qt platform ...:

                              I am running into this message attempting to run Houdini.

                              Please provide the full, exact message. There are subtly different versions of the message; some include additional details which can help pinpoint the exact issue.

                              Are all these vendors not properly installing their apps?

                              Most vendors probably installed their apps correctly.

                              However, it only takes 1 badly-behaved app to cause DLL Hell and ruin things for everyone else on that PC. You'll need to track down that badly-behaved app and do something about it.

                              Are users expected to modify their installations of these apps using windeployqt?

                              No, users are not expected to do anything. Software developers are expected to provide well-behaved installers.

                              Qt Doc Search for browsers: forum.qt.io/topic/35616/web-browser-extension-for-improved-doc-searches

                              1 Reply Last reply
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