I also had this prob a lot, with explorer trying to load itself atop litestep as shell.

I use 2xExplorer now so it's no issue.

But back then I think there's a checkbox in some windows setting somewhere that says launch explorer browser and explorer shell in separate memory spaces. I think that did it for me.

Also, someone recommended I add this line to my step.rc:
LSSetAsShell true

I think I lost explorer altogether then... not too sure. Can give it a try. Not a biggie to me tho since I don't use that hog of an MS app.