I have to apologize if there is an error similar to this one which has already been addressed, but I have done some research and have yet to find any exact similarities, so I opted for this - since I am rather new to Qt.
I have Windows 10, 64bit, and run the newest version of Qt, just updated with no more components which can be updated (done with the online installer and the Maintenance tool). However, this now comes with a problem: all old projects either freeze when opened, or crash the program. Thus far I have yet to have a problem with creating new projects, but they often freeze the program as well, if you open them again.
I have been able to take a screenshot of one of the errors Qt gives me, but I can't seem to make much sense of it, as i hadn't even built the project yet. I only opened it. Thus I added the error as an image, together with my current version of Qt and Qt Creator