Port conflict with Unifi OS Server

Jimmyjames

Pulling my weight
Oct 8, 2025
74
118
Michigan
Greetings,

I recently installed a Unifi switch and an AC Pro access point on my home network. I initially set it up with the legacy Unifi software and was soon prompted to download the more modern Unifi OS Server.

After installing the OS server, initialization was halted due to conflicts with a 4000’s range port and port 6789.

My instincts told me to uninstall several VMS softwares that I had been playing with but not really using. This resolved the issue with the 4000’s range port, but I’m still getting failures to initialize saying that port 6789 is still in use.

Any advice on how to free up this port?

Thanks !

Jim

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@Techie007L

You the man! I thank you much! I downloaded and installed the app and was very quickly able to attribute the issue to "OpenDHCPServer.exe", which appears to be the remnants of an application that I had used at one time to ping network devices directly.

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I attempted to uninstall "OpenDHCPServer.exe" and now get this windows dialogue box that pops up:



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hmmmm......maybe I will try reinstalling the DHCP software and see if there is an uninstall wizard that goes along with it. At this point it appears port 6789 is locked out
 
@Jimmyjames If that works, it's probably the best way. If not, it looks like it's installed as a Windows Service. You should be able to right-click the offending connection -> Go to process -> right-click the OpenDHCPServer.exe process -> Service -> Go to service -> right-click the selected/appropriate service -> Stop. Then right-click the service again -> Properties -> Start type -> Set to Disabled -> [OK] to keep it from starting again. It should be pretty clear, but do be careful as System Informer is a powerful tool, and accidentally changing the wrong services' configuration could break something or disable the system.
 
I was able to terminate the process on port 6789 with the software you recommended. The Unifi OS Server application is now initializing properly on the host PC.


You sir are the man. I appreciate you!