Message from Yetib:

I can only guess that there may be a problem with ALL PyQtTools (all of them showed 
(unknown) in Show External Tools), caused by a version issue. Indeed, PyqtTools requires 
5.13 version of Qt, while Eric6 installs 5.14.2 (due to WebEngine...)

Then PyQt5-tools should be installed BEFORE Eric6.

Note: PyQt5-tools is a Windows only package.

1. The pyuic5 issue could be related to the PyQt5 version. Please provide this 
information. The forms compilation works for me on several systems.

2. The "from .Ui_filename import UI_mainWindow" is a relative import. The '.' means to 
import from that file in the same package. A '..' would mean to look in the parent package 
and so on.

Hi, since version 20.3 (and 20.4), I get the popup "Compilation of form file 
failed" when invoking pyuic5 from right click popup menu. No further 
information. Compilation from a shell works fine however. Launching QtDesigner 
is OK. I switched to Python 3.7.7, I use WinPython distrib on Windows 10.
Another point looks weird: When I "generate dialog code" from the same menu, 
the import line looks like this
from .Ui_filename import UI_mainWindow
why is there a dot preceding the module name ?
I reviewed deeply all configuration of Eric6, project etc...but no idea.
please help, this is a very useful feature.