Unable to find the platform plugin while deploying application

Please_Help_me_D · wrote on 30 Jan 2020, 01:23

Hi,

I tried to deploy test application built with MSVC 2017 x64 on WIndows 10 x64 but windeployqt.exe says:

Adding Qt5Network for qmldbg_debugger.dll
Adding Qt5Gui for qmldbg_inspector.dll
Direct dependencies: Qt5Core
All dependencies : Qt5Core
To be deployed : Qt5Core Qt5Gui Qt5Network Qt5Qml Qt5Quick
Unable to find the platform plugin.

I read some sources in that topic such as here but I dont'use MinGW and still have such problem
Qt version 5.12.6
My Qt configuration:

hskoglund · 30 Jan 2020, 16:05

Hi, you don't really need windeployqt to make your Qt app run on another Windows 10 computer. Windeployqt iis a convenient tool but you can also copy the needed .dlls by yourself.

One way: first start your app, then download ListDLLs. Use it to create a list of all the .dlls your app is using.
Copy all the .dlls that are not from C:\Windows\System32 into the same folder as your .exe file. (The plugin .dlls need to be in their own subdirectories)

Go to the other Windows 10 computer, install the MSVC2017 64-bit redistributable. Then copy the folder from your development machine. With a bit of luck your app should start.

Please_Help_me_D · wrote on 30 Jan 2020, 16:05

@hskoglund Thank you!
I have not tried it yet but I'm going to
I believe that should work

Konstantin Tokarev · wrote on 30 Jan 2020, 18:01

Note that some dlls may be loaded lazily when particular feature of application is in use, e.g. Qt Multimedia plugins may be loaded only when you play something, or OpenSSL loaded when first https request is made

Please_Help_me_D · 3 Feb 2020, 17:44

@hskoglund I'm trying to use ListDLLs. I open cmd command line and go to the folder where my .exe is. Then I run the following command:

C:\apps\ListDlls\listdlls C:\Users\tasik\Documents\Qt_Projects\build-OpenMP_proba-Desktop_x86_windows_msvc2017_pe_64bit-Release\release\OpenMP_proba.exe

Where:

C:\apps\ListDlls\listdlls - path and .exe of listdlls
C:\Users\tasik\Documents\Qt_Projects\build-OpenMP_proba-Desktop_x86_windows_msvc2017_pe_64bit-Release\release\OpenMP_proba.exe - my exe

But I only receive:
Listdlls v3.2 - Listdlls
Copyright (C) 1997-2016 Mark Russinovich
Sysinternals

No matching processes were found.

hskoglund · 2 Mar 2020, 17:45

@Please_Help_me_D ListDLLs only care about the name of the program, not the path, so try:

C:\apps\ListDlls\listdlls Open

(also you don't have to type in all the letters of the program name :-)

Edit: also make sure that your program is running before starting ListDLLs

Please_Help_me_D · 2 Mar 2020, 18:00

@hskoglund this doesn't work either :(

C:\apps\ListDlls\listdlls Open

@hskoglund said in Unable to find the platform plugin while deploying application:

also make sure that your program is running before starting ListDLLs

Didn't understand that. COuld you please explain a little bit more?
If I just "double click" on OpenMP_proba.exe I get an error that I don't have some Qt ddl's.
This .exe file is created after I compile it in Qt in release mode.
By the way I use MSVC x64 compilator but Listdlls64 also doesn't work (is Listdlls64 is used to compile 64 bit apps?)

hskoglund · 3 Feb 2020, 18:28

You do not need to be able to run your program by double clicking on it, it's sufficient if can run your program from inside Qt Creator.
Also it doesn't matter if you use ListDLLs.exe or ListDLLs64.exe, they'll give you the same result.

Please_Help_me_D · 2 Mar 2020, 18:36

@hskoglund yes, something strange is going on on my pc :)
don't know how to lauch it correctly
I just tried to run listdlls with other .exe files but the same error I get. But I can run for example:

C:\apps\ListDlls\Listdlls O

The output:

Listdlls v3.2 - Listdlls
Copyright (C) 1997-2016 Mark Russinovich
Sysinternals

------------------------------------------------------------------------------
OneDrive.exe pid: 8332
Command line: "C:\Users\tasik\...\OneDrive.exe" /background

Base                Size      Path
0x0000000000f40000  0x185000  C:\Users\tasik\...\OneDrive.exe

etc.

Please_Help_me_D · wrote on 3 Feb 2020, 19:23

@hskoglund Well I could lauch it correctly only when I lauched it in Qt and while it was compiling I ran listdlls. But my .exe runs only 2 second so I have only 2 second to launch listdlls. Is there is a way use listdlls in other way?

hskoglund · wrote on 3 Feb 2020, 20:16

If your program starts, then you can put in a delay somewhere, for example:

for (;;);

so that you will have time to run ListDLLs