The maintenance tool (in qtcreator 4.7.0. IDE) notified me that there is an upgrade available for QtCreator which I accepted. The editor could never start again.

After some research I found that there was actually no update available for my system, since qtcreator 4.8.0 requires a newer version of macOS. The maintenance tool in qtcreator 4.7.0 should have never prompted me for an upgrade.

$ ./Qt\ Creator.app/Contents/MacOS/Qt\ Creator
Sorry, "Qt Creator" can not be run on this version of macOS. Qt requires macOS 10.12.0 or later, you have macOS 10.11.6.

 
Attached InstallationLog.txt for more details.
The upgrade in question started here:

************************************* Invoked: Tue Dec 11 08:45:29 2018