I get this and dont know how to correct the IK.
thank you very much for your support request.
The easiest way would be by creating a fresh UMotion project, and let the IK setup wizard do the IK setup for you. The IK setup wizard should generate a correct setup that does not have a dependency loop.
If you want to correct your setup by hand, make sure that the IK handles are not a child of a bone inside the IK chain. From what I see in the screenshot, your "IK_Hand_L" handle is a child of the "Bip001 L UpperArm" which is part of the IK chain. That would cause a dependency loop as the IK constraint is manipulating the rotation of the upper arm based on the "IK_Hand_L" position, but doing so will also alter the position of the IK_Hand_L as it is a child of the upper arm --> it's a loop. Make the "IK_Hand_L" a child of the "Bip001 L Clavicle" instead.
If you still get errors (for other bones), try to identify and solve the issue based on the same principles.
Let me know in case you have any follow-up questions.
Thanks for both answers!
Customer support service by UserEcho