If by preferences you mean Poser ini, try resetting preferences, set the preferences like you want, then set poser.ini to read only.

I have a lot of strange problems if P8 or 2010 opens in Screed, so I had to do that on both programs to force them to open in OpenGL. For me, once the program opens in OpenGL, I can switch to Screed and have no problems.
My problems were similar to what I had in P7 and the original PoserPro if I had "threaded optimization" turned on in my video card settings.
Although repeatable on my end every time, Smith-Micro couldn't duplicate the problem so I am resigned to live with it.