What does the 'tools produced empty toolpaths' warning mean?

Why this happens

The toolpath ran its math and found no material it could remove with that tool:

1. The tool is too big for every region in the selection (see the "tool will not fit" entry).
2. In a multi-tool pocket, a later tool has nothing left to do. The classic case is the same tool accidentally listed as both clearance and detail tool, so pass two has zero material remaining.
3. The wrong vectors were selected (empty selection, open vectors, or vectors on another layer or sheet).

The fix

1. Check the tool diameter against the smallest feature in the selection.
2. In clearance plus detail setups, confirm the detail tool is genuinely smaller than the clearance tool.
3. Re-select the intended vectors and recalculate. The form keeps all your settings, so fixing the selection is usually all it takes.

Pro tips

• This warning is per tool: in a two-tool pocket, one tool can produce a valid path while the other comes back empty, so read which tool the warning names.
• If you wanted a near-zero-removal finishing pass, give it a small allowance change so there is actual material to take.