A zsh script to reset troublesome ports on MacOS.

etc_reset.zsh

# etc_reset.zsh
# Version:  4.0 
#
# A script for resetting all ports and protocols for ETC software.
# Designed particularly for use with ETC Concert. 
#
# Created by Anthony Arblaster on 18 February 2025.
#
# Copyright Anthony Arblaster 2025. 
#    – Web: https://codebyanthony.com
#    – Mastodon: https://mastodonapp.uk/@aarblaster
#    – GitHub: https://github.com/aarblaster
#
# Licenced with MIT Licence.


#!/bin/zsh

# Run reset on common ETC used ports.
function etc_reset() {
	autoload -U colors && colors # All the colours

	# Helper: live progress while waiting for SLPD to stop
	wait_for_slpd_stop() {
		local max_wait=10  # seconds
		local interval=0.2
		local elapsed=0
		local bar_length=20

		printf "Waiting for SLPD to stop: "
		while pgrep -x "slpd" >/dev/null && (( $(echo "$elapsed < $max_wait" | bc -l) )); do
			local progress=$((elapsed * bar_length / max_wait))
			local filled=$(printf "%0.s#" $(seq 1 $progress))
			local empty=$(printf "%0.s-" $(seq 1 $((bar_length - progress))))
			printf "\rWaiting for SLPD to stop: [%s%s]" "$filled" "$empty"
			sleep $interval
			elapsed=$(echo "$elapsed + $interval" | bc)
		done
		echo ""
	}

	# Helper: live progress while waiting for SLPD to start
	wait_for_slpd_start() {
		local max_wait=10
		local interval=0.2
		local elapsed=0
		local bar_length=20

		printf "Waiting for SLPD to start: "
		while ! pgrep -x "slpd" >/dev/null && (( $(echo "$elapsed < $max_wait" | bc -l) )); do
			local progress=$((elapsed * bar_length / max_wait))
			local filled=$(printf "%0.s#" $(seq 1 $progress))
			local empty=$(printf "%0.s-" $(seq 1 $((bar_length - progress))))
			printf "\rWaiting for SLPD to start: [%s%s]" "$filled" "$empty"
			sleep $interval
			elapsed=$(echo "$elapsed + $interval" | bc)
		done
		echo ""
	}

	echo "$fg_bold[blue]Checking SLPD status...	$reset_color"
	if pgrep -x "slpd" >/dev/null; then
		echo "SLPD is running. Stopping it..."
		/usr/local/bin/stopslpd

		# Wait until it really stops (or timeout)
		wait_for_slpd_stop

		if pgrep -x "slpd" >/dev/null; then
			echo "$fg_bold[red]Error: SLPD is still running. Try again.	$reset_color"
			return 1
		else
			echo "SLPD stopped successfully."
		fi
	else
		echo "SLPD was not running."
	fi

	echo "$fg_bold[blue]Starting SLPD...$reset_color"
	/usr/local/bin/slpd &>/dev/null &
	wait_for_slpd_start

	if pgrep -x "slpd" >/dev/null; then
		echo "$fg_bold[green]SLPD started.$reset_color"
	else
		echo "$fg_bold[red]Error: Failed to start SLPD.$reset_color"
		return 1
	fi
}

This is the original script that is used in Terminal to reset ETC services and ports if you are having problems. This is in my original post here.
Feel free to use or mod. Or if you'd rather a little application you can go here.