I have tried both the installer and portable version 4.2.7.1 downloads, but cannot get G’MIC to work. My system is Windows 7 64-bit.

When clicking the Filter menu, the Start G’MIC-Qt and Re-apply the last G’MIC filter items are greyed out.

The G’Mic-Qt Integration screen points to the plugin that is included with the Krita download.

I also downloaded the Krita version of the plugin from https://gmic.eu/ and reconfigured Krita to point to that. But the G’MIC items on the Filter menu remained greyed out.

Here is a small portion of the kritarc file:
gmic_qt_plugin_path=C:/Program Files/Krita (x64)/bin/gmic_krita_qt.exe

[File Dialogs]
gmic_qt=C:/Program Files/Krita (x64)/bin

You don't have an open image, so every action that needs an image is grayed out, including g'mic.

Thank you.