Hi Mike,
The reason in nearly 99.9% is a bad/incompatible SU3+ package. MS/ASOBO has added a new feature in SU3 that ensures packages on the user system are loaded in the correct order, preventing overwriting previous packages/data.
We have written our own FAQ about that:
So, when you use a 3rd-party package that does not follow these development rules (starting with SU3 and following the SDK), you can run into such issues.
Your next step should be to find out which package is the culprit, but this can be very time-consuming because there is no clear sign/rule for how you (as a customer) can easily and fast identify it. I´m sorry.
Thanks for your feedback. Let me know when we can do more for you.
Cheers,
Richard