Unconnected "no connection" flag (KiCad ERC)

Diagnostic signature

Unconnected "no connection" flag

A "no connection" flag is present on the schematic canvas but is not attached to any component pin or label, triggering an Electrical Rules Check (ERC) warning.

What it means

The KiCad Electrical Rules Check (ERC) has detected a "no connection" flag that does not intersect with any component pin or label. "No-connection" flags indicate to the Electrical Rule Checker that the pin is intentionally unconnected and not an error. When a flag floats in the schematic canvas without being attached to a valid node, it serves no electrical function and triggers this violation.

Why it happens

This typically occurs when a user places a "no connection" flag to explicitly mark a pin as unused, but slightly misses the pin's actual attachment point. It can also happen when a component is moved or deleted after a flag was placed on one of its pins. Since the flag is a standalone graphical entity, moving the component leaves the flag behind as an orphaned marker in empty space, causing the ERC to flag it.

Minimal reproduction

(kicad_sch (version 20231120) (generator eeschema)
  (uuid "a1234567-b89c-d012-e345-f67890abcdef")
  (paper "A4")
  (no_connect (at 100 100) (uuid "12345678-1234-1234-1234-123456789012"))
)

How to fix it

Delete the unused 'no connection' flag or manually drag it onto the correct component pin so their attachment points perfectly intersect.

```schematic
(kicad_sch (version 20231120) (generator eeschema)
  (uuid "a1234567-b89c-d012-e345-f67890abcdef")
  (paper "A4")
)
```

Step 1

• Click the 'Unconnected "no connection" flag' warning in the ERC Violations tab to center the schematic view on the orphaned flag.

Step 2

• If the flag was left behind accidentally and is no longer needed, select the flag and delete it.

Step 3

• If the flag was intended for a specific pin, click and drag the flag until its exact center anchor snaps to the connection circle at the tip of the unconnected pin.

Step 4

• Re-run the Electrical Rules Check to confirm the warning is resolved.

Upstream references

Schematic Editor | 8.0 | English | Documentation - KiCad Docs

Schematic Editor | 7.0 | English | Documentation - KiCad Docs