When opening a step file in 2017 i get a mystery part that attaches itself into the assembly. How can I stop this?
Check the part and assembly templates. I believe you already have that feature/part inserted in those templates.
It must be a suppressed part that's unsuppressed during the save-as step process. Delete or suppress it.
Highlight every part in the feature tree to see if it's connected to another component, could have been a closed sketch off to the side that you didn't notice....
What shape is it?
Thank you all, it seems to have been a corrupted assembly template. I created a new template and all seems well now.
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