thanks to you both . i haven tried DEMANDLOAD as i read the message too late . I might try next week .
i dont believe the issue is related to content of support folder . (besides, it is normal) . to my knowledge acetmain.cui has graphic interface , not core commands.
what i did finally was switch to another session : then expresstools loaded .
but some of acad behaviour was strange . Adcenter and toolpalettes windows were sort of difficult to move even though LOCKUI is set to 0 .
I am starting to think this is an issue with this pc. on any session system gives error messages, and i am unable to load profiles because of registry error .
