Maya 2018 splash screen disappear - wont start

Question

I had problem that Maya 2018 gave me the following error message when I tried to start it:

"maya" could not load the qt platform plugin "windows" in "".

Then I have downloaded the 2018.5 Update via the Autodesk Desktop App.
But now Maya gives me the splash screen and says it is loading and then it disappears and it won't start.

The message under the version number, so "Maya loading.", does not change.

How do I fix that?

Splash screen:

Answer 1

Recently I wanted to try to develop a plugin for Maya and messed with the Windows' environment location for MAYA_LOCATION and DEVKIT_LOCATION. I just remembered this and deleted them after this page(https://www.techjunkie.com/environment-variables-windows-10/).

For the setup for the environment variables I used your documentation(https://help.autodesk.com/view/MAYAUL/2019/ENU/?guid=__developer_Setting_up_your_build_Windows_envir...).

Now Maya 2017, Maya 2018 starts properly, Maya 2019 as before!