[Interest] Windows deployment. Failed to start because of missing platform plugin...

[Sze Howe Koh]

On 28 August 2015 at 21:20, Bo Thorsen <bo at vikingsoft.eu> wrote:
>
> Den 28-08-2015 kl. 10:01 skrev Igor Mironchik:
> > I'm trying to deploy Qt Windows application. And it failed to start with
> > the next message...
> >
> > This application failed to start because it could not find or load the
> > Qt platform plugin "windows".
> >
> > Reinstalling the application may fix this problem.
> >
> > Platform plugin is exist in ./platforms/qwindows.dll
>
> It has to be in plugins/platforms/qwindows.dll.

Igor's path is perfectly valid.


> > How can I solve this problem?

Let's check first: Does your app work properly if you run it from Qt Creator?

If you have Qt in your PATH, remove it.

Also try windeployqt like Samuel suggested.

If that still doesn't work, try these manual steps:
https://wiki.qt.io/Deploy_an_Application_on_Windows


> When I hit this, I copy every dll from Qt to my bin dir and every plugin
> to the plugins dir. If that runs, then you can start deleting stuff and
> see if your application still runs.
>
> For example, I have this:
>
> C:\Prog..\VikingSoftware\Pokerformance\
>    pokerformance.exe
>    Qt5Core.dll
>    Qt5Gui.dll
>    Qt5Network.dll
>    Qt5Sql.dll
>    Qt5Widgets.dll
>    plugins\
>      platforms\
>        qwindows.dll
>      sqldrivers\
>        qsqlite.dll
>
> This works for me with Qt 5.5.

Are you sure? Did you use a custom configuration or call
QCoreApplication::addLibraryPath()? By default, the application will
look for <PWD>\platforms\qwindows.dll but not
<PWD>\plugins\platforms\qwindows.dll.

Note also that Qt tries to load plugins from the folder where you
installed your development files (e.g.
C:\Qt\5.5\mingw492_32\plugins\platforms\qwindows.dll). If you're
testing your deployment on a dev machine, make sure you temporarily
move the dev DLLs somewhere else.


> I hope this helps.
>
> Bo Thorsen,
> Director, Viking Software.

Regards,
Sze-Howe