Qt platform plugin windows fail or windows 8 vs windows 10

Psy_Duck

Hello all, again (well, lately I often write about problems)
So, i have:
one project (standart Qt widget);
two system: windows 8 (64-bit) with Qt 5.5.0 Mingw32bit and windows 10 (64-bit) with Qt 5.5.1 Mingw32bit
I build project at win8 and win10, collect folder (libEGL, libgccc_s.., libGleSv2, libstdc++, libwinpthread-1, Qt5Core, Qt5Gui, Qt5Widgets, platforms/qwindows or plugins/platforms) by files of mingw each system (did not mix files, it is meant). (pic for example win8 win10.
And i launch program at on different systems.
So program compiled by win8 with win8 libs work at: win8-64(Qt install), win8-32(Qt install), Ubuntu(at wine start - work), windows7 (Qt not install). Doesn't work at win10-64 (Qt install).
program compiled by win10 with win10 libs work at: win10-64(Qt install), Ubuntu(at wine start - work), windows7 (Qt not install). Doesn't work at win8-64 and win8-32 (Qt install both).
program compiled by win10 with win8 libs (Qtcore, qtwidget, qtgui) work at win8.
Error looks like win 8 like win 10
Questions:

Why?
How?
what to do, so that the win8 program could work at win10 and win10 program could work at win8?
If somebody know what i doing wrong - answer me please.
And yep, i something hear about that old Qt compiler doesn't work at win 10, but qt 5.5? and why win 10 program doesn't work at win 8? Or need have 2 complect qwindows for win8 and win10 and if win8 -> change LibraryPath?

Psy_Duck

@Psy_Duck help?

JKSH

@Psy_Duck said:

Error looks like win 8 [like win 10]

Your program is trying to load the wrong version of Qt DLLs.

Doesn't work at win10-64 (Qt install).
...
Doesn't work at win8-64 and win8-32 (Qt install both).

Remove Qt from your PATH.

Psy_Duck

@JKSH Hi again
At win 10 i find C:\Qt\Tools\mingw492_32\bin; and delete, but it's not help for win8 project they stay don't
work

in win 8 that text in my path

C:\ProgramData\Oracle\Java\javapath;
C:\Windows\system32;
C:\Windows;
C:\Windows\System32\Wbem;
C:\Windows\System32\WindowsPowerShell\v1.0;
C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;
C:\Program Files (x86)\Skype\Phone;
C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit;
C:\Program Files\Microsoft SQL Server\110\Tools\Binn;
C:\Program Files (x86)\Microsoft SDKs\TypeScript\1.0\

I haven't QT in path at win 8

hskoglund

Hi, if you try to run a Qt 5.5.1 .exe file on another computer that has Qt 5.5 installed this will fail with a platform plugin error if the Qt 5.5.1 and the Qt 5.5 are installed to the same directories on the 2 different computers.

So to get rid of this error:

you can run windeployqt on your .exe file (it will give you a patched Qt5Core.dll) use those .dlls to deploy to other computers, this will work
reinstall Qt 5.5 or Qt 5.5.1 to another place on C:, so that the 2 different installations on your 2 different computers are not installed to the same place
reinstall so that both the computers have the same version of Qt, either 5.5 or 5.5.1

Psy_Duck

@hskoglund first method, windeployqt and add libcc libs and it's work!
Thank you, again.
P.S. but when i release and windeploy program with sqldriver (program can work an win 8, it's good) and release program in qt again -> "could find or load the Qt platform plugin "windows"". Well done)

hskoglund

Good! About your P.S. when you have done windeployqt on your .exe file, then every time after that, if you go into Qt Creator and edit/rebuild your program, then to be safe, you should run windeployqt again.

Psy_Duck

@hskoglund said:

Good! About your P.S. when you have done windeployqt on your .exe file, then every time after that, if you go into Qt Creator and edit/rebuild your program, then to be safe, you should run windeployqt again.

yep, it's work! thank you!