Thanks cavalierlife,
I made sure, that I have the latest update 2.6.6
I have gone through the migration process (but, as an additional information: The “fontawesome…” tab is not displayed in the tool.)
And I checked “Load Font Awesome 4 Support” is set to Yes.
I had considered all this before, but unfortunately there was no change in the problem at the moment. The icon library remains empty ??
Joerg-Michael