The first time you run the tool, Windows Defender Firewall will likely pop up asking for permission. You must allow access on (and Public if you are troubleshooting a direct connection).
If you try to run the .jar file or the included .bat file and see a "Java Exception has occurred" message, it usually indicates a conflict between the tool’s code and your current JRE. This is often due to the way the original tool was obfuscated, using variable names that modern Java versions now consider illegal. How to Install and Run UBNT Discovery Tool v2.5.1
Override Windows 10 DPI scaling.
: A free, popular third-party alternative designed specifically to replace the legacy UBNT tool. It works on Windows, macOS, and Linux.
: While not Ubiquiti-specific, it can locate devices by their MAC addresses if you know the manufacturer's OUI. ubnt-discovery tool not working on modern JREs (even JDK8)