I’m trying to retarget a mesh, and I get the error as per the title. I have previously made a retargeter with the exact same rig and it worked fine. I cannot figure out what I’m missing, as both meshes very clearly have root bones, and a chain map to them. (Please ignore the fact that it is a minion mesh)
bumping because I have the same issue
Retarget Animations in Unreal Engine 5.2 (Tutorial) - YouTube for anyone wondering, it goes through the process step by step
Thats the video I was watching when I ran into this issue and couldn’t right click cuz everything is greyed out with this error lol.
open the Blueprint IKRig click in pelvis after click on right mouse button and select
“Set Retarget Root” save and open the Blueprint “IK Retarget” again then resolved 
Bro u save my day !
Fixed the problem for me also yay 
. (5.3.2) Appreciate it @Wertandrew
(post deleted by author)
Did you do this for both source AND target?
iirc yes, but usually one is setup correctly and one isnt
