Here is how to get it working again without compromising your system's security. The Problem: Java 8 Update 281+ The primary issue is that Java 8 Update 281

Windows 10’s updated security policies throttle Java applets and WebStart. Because v2.5.1 launches as a hybrid application:

Oracle Java 8 Update 202 (the last free version for commercial use, but fine for personal/lab).

Windows 10 updates may have broken raw socket support. Consider:

Before using the Ubnt Discovery Tool v2.5.1, ensure your system meets the following requirements:

Legacy hardware demands legacy tools. The UBNT Discovery Tool v2.5.1 may be a decade old, but on a modern, patched Windows 10 machine—armed with the right Java 11 build, specific JVM flags, and careful firewall rules—it still works like a charm. Ubiquiti’s newer offerings cannot touch it for pure Layer 2 discovery of airMAX M/XM equipment.