for some time i have a problem with MoI. files won't open at all, or not properly...

possibility A)
- the 3D-models (no matter what file format) don't open at all
- in the activity monitor first CPU is at high percentage and memory is rising. sooner or later memory get's stuck at a certain point and CPU is turning to zero.
- the software doesn't seem to be frozen (when pushing alt+cmd+esc)
- nothing further happen

possibility B)
- the 3D-models (no matter what file format) only open partly.
- the software is not frozen and in the activity monitor there is no suspicious activity.
- only a part of the file was opened (in the browser i don't see all objects and layers).
- apart from that MoI seems to have full functionality

version & enviromet:
first i was working with Moi v3.0 on OS 10.7 and upgraded to 10.8 (since MoI worked fine on other computers with 10.8). but this did't solve the problem.
now i upgraded to 10.11 and also updated MoI to v3.1.
the issues were the same in any of these OS/software combinations.

how i tried to solve the problem:
- i tried to re-install MoI => no improvement
- i deleted the plist entries => first i had the impression that this helps, but i'm not sure anymore
- i did start the system in "safe mode" => just in addition to the plist approach

with a combination of the later two actions, sometimes MoI seemed to work again. but sooner or later (usually sooner) the problems are back.
the only thing that works, is starting up the (same) computer with a new (and clean) user.
with this different user on the same computer i have no problems with MoI at all.


did anybody have similar problems so far? could you solve it? and how?
i don't really want to delete my normal user profile and build a new one up...