I have a very weird problem. Ive got a an Ubuntu 14.04 running on VirtualBox 4.3.20 r96997. I installed QT Creator a while back and was working with it fine until today. Now when I try to start it, the screen is completely unresponsive, and it endes up freezing (just the QT Creator screen, ubuntu keeps working fine)
I have read in a couple of places that this could be because the welcome mode doesnt play nice with virtualbox 3d hardware acceleration:
Why does Qt Creator 3.0.0 Welcome Mode not work in VM?
http://qt-project.org/forums/viewthread/37412
But im starting ubuntu with the 3d hardware acceleration disabled, and Ive also tried starting it direcly from the terminal by going to the install folder and doing:
./qtcreator -noload Welcome -noload QmlDesigner -noload QmlProfiler
But it also freezes. And the weird thing is that it worked yesterday, and I havent installed any updates or changed the system, it just appears to have stopped working. Any suggestions?
Posting my comment as an answer, since OP confirmed it works.
Delete the configuration directory for QtCreator - it's somewhere in ~/.config/