I designed a propeller blade for model aircraft (type folding prop which has a hinge at the root of the blade). I want to create a mold, so followed the steps: created parting line and parting surface. That went down well after some fiddling around. The step tooling split fails and leaves me with the error message "The sketch should not contain a single closure contour". However when I check the sketch with the check tool, it does not find anything wrong with it. Now I am really stuck... Put in a lot of hours to learn Solidworks and designing this. And so determined to complete the work. But I need some help here.
With respect to the design: the 3mm shaft sticking out of the part is intentional and has no draft. This is how it should be.
Someone has any suggestions, that would be really welcome. Attached is the design created in Solidworks 2019-2020.