How to Fix Animator IK Not Working in Unity

Animator IK that does nothing usually has the IK Pass off or is set in the wrong place. Here is how to fix it.

How to fix it

1. Enable IK Pass on the layer

The animator layer must have IK Pass enabled for OnAnimatorIK to be called and IK to apply. Without it, your IK code runs nothing. Turn it on for the relevant layer.

2. Set goals and weights in OnAnimatorIK

Call SetIKPosition, SetIKRotation, and the corresponding weights inside OnAnimatorIK each frame. Setting them elsewhere, or leaving weights at zero, means the IK has no influence.

3. Use a humanoid rig

Animator IK for hands and feet works with a humanoid avatar. A generic rig does not expose the IK goals. Configure the model as humanoid so the IK targets exist.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unity error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.