@aha_1980 Here's how I bootstrapped new working settings for QtCreator. On Windows the settings reside in <user>\Appdata\Roaming\QtProject, which contains files QtCreator.db, QtCreator.ini and directory qtcreator with lots of subdirectories, xml files etc. Renaming that directory then running QtCreator created a new settings directory (from a template kept in the Qt distro) . After that, QtCreator started behaving normally, though of course without any memory of previous projects or kit associations. Copying the QtCreator.ini file from the renamed directory restored those memories but did not make the bad behavior come back. Apparently the root problem is an incompatibility between Qt Creator 4.10.2 and some old file in the settings folder. In my case those files were created years ago by QtCreator 3.5. And since 3.5 does not even support VC 2015, I guess it was high time for a change.