Animation starts ok on my pc same steps my other pc but doesn't work?!

my steps are
import an object set it to homanoid check if all the bones are set and ready
get back to scene add animator component to the object (parent) then add animations to the animator
and it works like a charm but only on my first pc

same steps i swear to god they are the same double checked triple checked 100 times

it just doesn’t work

the bones are set to their places and everything is green but the only issue is that the animation from the unity asset doesn’t work

i used the same animations on both
the same model and tried multiple models
the same steps
the same version of unity and i tried two 5.0.2 and 5.1.0 beta

and the error is in the animation windows the bones are yellow and (not found)

but on the first pc they are black and working

somebody can tell me what the heck is going on?

Fresh install solved the issue