[Interest] Qt permanently broke on computer

[Jason H]

I tried to port an app on a Win10 PC. That went well. Then I tried to deploy (windeployqt) it.

Now when I run it in creator I get:
10:26:28: Starting C:\Users\Admin\Projects\build-phidget-spinner-Desktop_Qt_5_15_2_MinGW_64_bit-Debug\debug\phidget-spinner.exe ...
qt.qpa.plugin: Could not find the Qt platform plugin "windows" in ""

I have deleted the C:\Qt dir and re-installed.
I have cleaned the app source dir and deleted the shadow build dirs, deleted the .pro.user file,
I launched QtC from the start menu.

I have no idea how to get this working again.