Animation deformed after importing...

When I import my weapon and rigged hands (one 3ds max file) into Unity, the weapon animation is working good, but the hand animation is distorted, like the arm goes side-ways instead of forward, and one doesn’t even move… When I show the file in the folder its in and open it, the animation looks fine… This is a very weird and serious issue! Any help will be appreciated…

I have also had this problem in the past, the way I have fixed it is to just export the file as a different type. I tend to have the least issues and highest compatibility with the FBX format.