The tool sends raw packets. Windows Defender may block it. Add the tool’s folder to Defender’s exclusion list before launching.
The most common reason the UBNT Discovery Tool fails to launch on Windows 10 is a Java architecture mismatch.
The short answer: The UBNT Discovery Tool v2.5.1 is a 32-bit application. ubnt discovery tool v2.5.1 and java on windows 10
Most modern Windows 10 installations utilize a 64-bit browser and automatically install the 64-bit version of Java by default. While having 64-bit Java is great for security and performance, the UBNT Discovery tool cannot "see" or utilize it. It strictly requires the 32-bit Java Runtime Environment (JRE) to function.
Solution: Override Windows 10 DPI scaling. The tool sends raw packets
Oracle hides old versions, but you can find Java 7 Update 80 (32-bit) on trusted archive sites. Install it to:
C:\Program Files (x86)\Java\jre7
Security note: Keep this Java version offline. Only run the Discovery Tool on an isolated management VLAN or trusted network. Security note: Keep this Java version offline
If distributed as an .exe or installer:
| Issue | Likely Cause | Solution |
|-------|--------------|----------|
| Tool does not open / No window appears | Java 8 not installed or default Java is newer version | Uninstall newer Java versions or force Java 8 as default |
| “Java Exception: No suitable network interface” | Windows firewall or admin rights | Run as Administrator; allow javaw.exe and DiscoveryTool.exe in Windows Defender Firewall |
| Devices not found despite being present | Network adapter not in promiscuous mode | Try a different adapter, disable virtual adapters (Hyper-V, VMware), or use a simple unmanaged switch |
| GUI flickering / slow refresh | Java 8 rendering issues on Windows 10 | Update to latest Java 8 patch (e.g., 8u301 or newer); disable display scaling for the tool |