Burr,

It'll be better if you attach your model, but I tried to reproduce it from your screen dump and had no issues with filleting through the seem.
Are you picking the edges you want to fillet or are you just picking the solid then fillet?

When I pick the solid then fillet command (when you want to fillet every edge) nothing will happen, but when picking the specific edges
you want to fillet then it should work, the hole through the seam would have 3 edges, all 3 must be picked.




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