Supports Stuck or Fused to the Print

Likely causes, most common first

1. Top contact Z distance too small or zeroMost common
   Prusa explains the slicer leaves a small gap so supports break off more easily, and that reducing it improves the surface but makes supports harder to remove. It suggests values of 50 to 75% of the layer height Rule of thumb for its slicer.
2. XY separation too smallVery common
   Prusa: a larger XY gap reduces contact area and makes supports easier to remove and less prone to fusing to the model. Fusing on vertical walls points here.
3. Dense or thick interfaceCommon
   OrcaSlicer: more interface layers give a flatter supported surface but are harder to peel off; zero interface is easiest to remove but leaves the roughest overhangs. A solid interface spacing (0) maximizes contact.
4. Hard-to-remove support pattern or a sheathCommon
   Prusa calls rectilinear usually the easiest to remove, honeycomb somewhat difficult and rectilinear grid harder; a sheath around supports also makes removal harder.
5. Supports growing from the model surfaceOccasional
   Supports that start on the model touch its surface. The bottom contact Z distance sets the gap there, and OrcaSlicer notes bottom interface layers protect that surface from the support body.

Fix it, one change at a time

1. Set a real top contact Z distance. Make sure it is not zero for breakaway supports. In PrusaSlicer, start at 50 to 75% of the layer height Rule of thumb; in other slicers start from the maker's preset for your printer and nozzle. OrcaSlicer rounds Z gaps to whole layer heights unless independent support layer height is enabled, so a small change may do nothing; preview to check.
2. Widen the XY separation if supports fuse to side walls.
3. Loosen the interface. Reduce the number of top interface layers or increase interface spacing, then preview. OrcaSlicer's concentric interface pattern peels off in one piece and leaves no line ends on the surface.
4. Use an easier pattern. Switch to rectilinear, remove any sheath, or try tree or organic supports, which Prusa describes as easily removable and unlikely to scar the surface.
5. Increase support pattern spacing to make removal easier. Prusa warns that too much spacing makes the interface sag between support lines.
6. Reduce how much support you need. Reorient the part, split it with the slicer's cut tool, block supports where they are not needed, or use support on build plate only. See Print Orientation.
7. For a perfect underside, consider a soluble or breakaway interface material on a multi-material printer, where a zero Z gap is intended. See Soluble Supports: PVA and BVOH.

Confirm it is fixed

Print a small overhang test or the supported region of the real part with the new settings. Supports should come away by hand or with pliers, leaving a surface you can clean up with light trimming. Look at the supported surface too: if it has become rough or saggy, the gap is now a little too large; Prusa suggests raising the top interface layers to 3 or 4 Starting point for a more solid support top before you shrink the gap again.

Why it happens

Supports are made from the same plastic as the part, printed at the same temperature, so they bond to it the same way the part's own layers bond to each other. The only thing that keeps them removable is a gap: a small vertical air gap between the top of the support and the part (the top contact Z distance), and a horizontal gap at the sides (the XY separation). The overhang is printed onto the support with just enough contact to hold it up, and not enough to weld.

That makes support settings a trade-off between removal and surface finish. Prusa's own advice for a rough surface above supports is the reverse of the advice for fused supports: reduce the gap, add interface layers. Neither end is wrong. Find the gap that releases cleanly on your printer and material, then improve the surface with interface layers and cooling rather than by closing the gap.

Prusa also notes that the slicer treats the surface above a support as a bridge, so bridge cooling and speed affect how it looks. If the supported surface droops rather than fuses, read Overhangs Drooping, Sagging or Curling Up. For every support option in one place, see Support Settings.