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

Question

I tried making an executable file of my program but there are some errors which I did not understand or could not find solutions of. I used my .exe file onto another computer and there was an error. I made my program through QtCreator (v 5.1.1)with my Windows 7, 64-bit laptop. There was an error when I used it in 2 32-bit laptops.

The error message says:

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

Available platform plugins are: minimal, offscreen, windows.

Reinstalling the application may fix the problem.

I already created a new folder called "platforms" containing "qminimal.dll", "qoffscreen.dll" and "qwindows.dll" in the same level of my .exe file. I also pasted in the same level the other DLLs that my program needs.

Answer 1

We had exact same problem with Qt5.3.

Problem arised when we've rebuilt the Qt to reduce dependencies (e.g. Qt5Positioning, Qt5Sensors). Created dlls were copied to different directory (source for installation), but we forgot to copy also newly created platforms plugin dlls.

The problem was fixed by using all dlls from same Qt build (with same configuration).

Your problem is probably the same: mixing dlls from different Qt builds (e.g. different configuration, version,...).

Answer 2

In Qt 5.2, there is a tool that can be used for deployment on Windows: windeployqt. It will be in the bin folder of your Qt installation. It greatly simplifies deployment, so if you don't mind downloading a newer Qt version, I'd highly recommend it. It may even work with an older Qt version, but I haven't tested it.