I trying to create a fairly simple extrusion, but I get a thin feature. Any ideas on how to overcome this thin feature?
it's probably an open contour.fully define the geometry (make the sketch black).
Leszak is almost certainly right. It sounds like your sketch isn't a closed profile. If you're still having problems can you post a screenshot of your sketch, or the part file itself?
While in sketch edit mode, go to Tools > Sketch Tools > Check Sketch for Feature and that would find the issue for you.
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