This is the fix if your SFM session opens in the engine window and the main Editting (QT Port) window is not visible:
1. SFM is made up of 3 main windows
a) the Engine Window
b) the QT Port(the editting screen we associate with being the main screen for SFM) and
c) the Particle editor
In most cases we tell SFM to automatically hide the engine window, but for some of us we don't get the chance. The Engine window takes priority and blocks off everything else. (You can tell your in the engine window by the menu text, it's orangish yellow. If you click Lyra's picture link above you'll see what I mean). Most ppl think that SFM is broken as in this case when this happens and it's been quite the struggle to find out how to fix it, but here it is....
In the engine window, select Windows, then click QT Port
This will cause the QT Port (the editting window we all know and have learned to love) to open.
Now it may open with all or some of its tabs displayed or none of the familiar tabs at all. The way we know it is the QT Port is that the menu text is Greyish-White.
or Like this:
If the QT Port opens in a format that you weren't expecting, just click Window > Then Layouts and select Return to Default Layout.
Once that is done, Click Windows, select Engine Window and ensure that Auto Hide Engine Window is checked on
Now that that is done, Close SFM and Restart. SFM should start normally by displaying the QT Port (or the Editting window we all Love!!!)