I create an .exe file by cx_freeze and copy all the .dll file I can find to the folder which includes that .exe.
The problem is I can run the .exe on my computer perfectly but can't run on another computer by using the same folder. I have tried 3 different computers and all pop up the error message "This application failed to start because it could not find or load the Qt platform plugin "windows" in ""."
It really confuses me why the problem exists on another computer but doesn't exist on mine.
I ran into the same error and solved it with a different method than those mentioned in other posts. Hopefully this will help future readers.
BUILD:
Windows 10 (64bit) Minicoda (using python 3.9.4) (pkgs are from conda-forge channel) pyqt 5.12.3
VScode 1.56.2
My scenario:
I was building a GUI application for some embedded work. I had two machines that were used for development (same OS and architecture), one had zero internet connection. After packaging up my environment and installing on the offline machine, I ran into the error that you got.
Solution:
locate the qt.conf file in your conda environment. for me: C:\Users"name"\miniconda3\envs"env_name"\qt.conf
Make sure the paths are correct. I needed to update the "name" as this was left over from the old machine.
Hopefully this helps someone.
Could not find or load the Qt platform plugin "windows" -- cx_freeze(.exe)