Mechanim Rig Rotation

Hi, all!

I've been working in Unity for a while now and I have almost torn my hair out time and time again due to an orientation issue with mechanim, (I use blender to model + rig). Usually everything works out and it is all set up and running smoothly, and then I go into Blender and edit a bone or something (I have no idea what does it).

I then pop back into Unity and my rig will be rotated 180 degrees on the up axis. Then, the back walk makes the character move forward, so on and so forth.

Try as I might, I cannot seem to fix these rotational issues and I'm at my wit's end here

I would really, REALLY appreciate some help for a solution to this problem because I am so frustrated I could cry. Every time I go back into Blender and edit the root bone to a correct rotation and re-do the animation, Mechanim keeps up with me and just manages to flip that. I cannot solve the issue.

Please help, thanks- YA