Missing footprint

Diagnostic signature

Missing footprint

The KiCad PCB Editor Design Rule Checker (DRC) flags a 'Missing footprint' violation when a schematic symbol has no corresponding physical footprint placed on the board layout. This usually happens if the board has not been updated from the schematic, or if the assigned footprint is invalid.

What it means

This diagnostic signifies a loss of parity between the schematic and the board layout. A symbol exists in the schematic that demands a physical footprint, but the Design Rule Checker cannot locate a footprint on the PCB with a matching reference designator. As a result, the board design is incomplete and does not accurately reflect the intended circuit.

Why it happens

This warning is emitted during DRC when the schematic parity checks look for differences between the schematic and the board. The rule triggers because a footprint is expected based on a schematic symbol but is absent from the board. Common causes include: (1) A new component was added to the schematic, but the user has not yet synchronized the board using the 'Update PCB from Schematic' command. (2) The user intentionally or accidentally deleted the footprint directly from the PCB layout, breaking the synchronization. (3) The schematic symbol's reference designator was modified, leading to a mismatch where the original footprint on the board is now considered an 'Extra footprint' while the new reference designator is flagged as a 'Missing footprint'. (4) The footprint assigned to the symbol is missing from the active library table, preventing the update process from successfully importing it.

Minimal reproduction

Symbol R1: Value: 10k, Footprint: Resistor_SMD:R_0603_1608Metric. Action: Delete R1 from the PCB layout, then run DRC.

How to fix it

Ensure the schematic symbol has a valid footprint assigned, then synchronize the schematic and the PCB to place the missing footprint.

```KiCad Design
Symbol R1: Value: 10k, Footprint: Resistor_SMD:R_0603_1608Metric. Action: Run 'Update PCB from Schematic' (F8), place R1 on the PCB layout, then run DRC to ensure 0 violations.
```

Step 1

• Open the schematic editor and locate the symbol that corresponds to the missing footprint.

Step 2

• Open the symbol properties and verify that the 'Footprint' field contains a valid footprint assignment.

Step 3

• Switch to the PCB Editor and invoke the 'Update PCB from Schematic' command (usually F8).

Step 4

• Verify that the dialog does not display any library lookup errors, and click 'Update PCB' to pull the missing component onto the board.

Step 5

• Place the component in the layout.

Step 6

• Re-run the Design Rule Checker to confirm the parity violation is resolved.

Upstream references

PCB Editor Documentation: Schematic parity DRC checks

Issue #16581: Bug (?): Update from schematic does not import missing footprint into PCB

KiCad Source Code: pcbnew/drc/drc_item.cpp