diff --git a/scripts/publish-update.sh b/scripts/publish-update.sh
index 37c70d9..4849151 100755
--- a/scripts/publish-update.sh
+++ b/scripts/publish-update.sh
@@ -367,6 +367,10 @@ if [[ "${SPCTL_STATUS}" -ne 0 ]] || ! grep -qi 'accepted' <<<"${SPCTL_OUTPUT}";
 fi
 
 TEAM_IDENTIFIER="$(codesign -dv "${APP_BUNDLE}" 2>&1 | awk -F= '/^TeamIdentifier=/{print $2}')"
+if [[ -z "${TEAM_IDENTIFIER}" ]]; then
+    echo "No TeamIdentifier on ${APP_BUNDLE} — the build is not signed with a team identity; refusing to publish." >&2
+    exit 1
+fi
 
 echo "==> Writing ${APPCAST_PATH}"
 python3 - "${VERSION}" "${ZIP_URL}" "${SHA256}" "${NOTES}" "${PUBDATE}" "${APPCAST_PATH}" "${NOTARIZED}" "${TEAM_IDENTIFIER}" <<'PY'