Why do my embroidery outlines not line up?

Outlines that miss the fill are a registration problem: the fabric moved relative to the needle between the fill and the outline.

The usual cause is movement in the hoop. Fabric that was not taut, a hoop screw that loosened, or a heavy garment hanging off the machine bed and dragging the hoop as it moves. Rehoop with the fabric firm, tighten the screw after hooping, and support the weight of the garment.

Insufficient stabiliser is next. A dense design pulls the fabric inwards as it stitches. If the stabiliser cannot resist that, the fill area shrinks slightly and the outline, stitched afterwards at its original coordinates, lands outside it. Use a firmer or an additional layer, and a cut-away on anything with give.

Speed and thick fabric. On towelling, caps and heavy seams, the needle deflects. Reduce speed, particularly through dense sections and over seams.

Hooping too tightly is its own fault. Stretching the fabric in the hoop means it relaxes after removal and every element moves relative to every other. Taut is right; stretched is not.

Check the mechanical basics as well: hoop clipped properly into the arm, nothing obstructing its travel, and the fabric not caught under the machine bed.

Some of it is the design. Cheaply digitised files lack pull compensation, so shapes are stitched at their drawn size and close up as the thread tightens. If one design always misregisters and others never do, it is the file.

Test on scrap with the actual fabric and stabiliser.