I recently installed Qt, actually I am developing a C++ project which was written to comply with Qt 5.15.2, so I downloaded that one, and installed Creator 8.0.1 (Enterprise) too. Creator does not start, but it welcomes me with this message:
The application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Available platform plugins are: direct2d, minimal, offscreen, windows.
I already tried with reinstalling related Qt components, it does not help. Also, I installed Qt Creator 9.0.0-beta1, but that gives the exact same error message.
I tried to google the error message to get an answer, but eveywhere (e.g. https://ugetfix.com/ask/how-to-fix-application-failed-to-start-because-no-qt-platform-plugin-could-be-initialized-error-in-windows/) they say I should search for some kind of "pyqt5_tools" folder, and copy the contents of a subdirectory inside Python install directory on my computer into a subdirectory in that folder... but I do not have Python on my computer, and it has nothing to do my project or anything. The project I am working on is in C++, and I would only like to use the Qt Creator application for that. Should I download Python or something for this? How exactly is Python related to Qt Creator at all?
(Anyway, Qt itself works fine, I can develop my code using VSCode and Qt libraries, build and debug them, but I would like to use Creator as an IDE because for certain things it is easier for a Qt app development.)
My machine is nice and new, just freshly reinstalled it a few months ago, 480GB SSD as main drive, 8GB RAM, Intel i7-2820QM CPU. I am using Windows 8.1 Pro with all latest updates.
I appreciate any help. Thanks in advance!
QtCreator 8.0.1 does not support Windows 8.1 (because it is developed in Qt 6, which supports only Windows 10 and newer, see https://doc.qt.io/qt-6/supported-platforms.html).
You will probably need to download and install older versions of QtCreator. You can find some of them here https://download.qt.io/archive/qtcreator/
Alternatively you should upgrade to Windows 10, which is definitely a more future-proof solution for you...