Problem importing the blender model into unity I followed a tutorial in youtube into creating the rig and animations of a humanoid model. I successfully finished the tutorial but when I import it in unity, and make the rig humanoid I get this error. 

Causing the whole rig to malfunction. I don't understand because the bones are complete. Tried renaming the foot bones but it does not fix the problem.

Here's the blend file: model
In Blender you need to rename the bone AND any weight groups you have already assigned when parenting to the armature. The armature bone name needs to match the weight group created for the mesh, otherwise the foot won't be moving with the bone in Blender or in Unity.

Additionally in Unity you can go to Rig-tab and click the button configure the avatar where you can manually assign the left foot to the bone that your model has. But I assume if you fix the weight group naming first (which is mandatory for the rig to work) Unity should be able to correctly automatically detect the foot afterwards.

Finally after you have configured the avatar you can proceed to importing the animations.