Universal Print Connect 2.4.9459.590 Service keeps stop /start

Hi,

Thanks for sharing the screenshots — they actually reveal the root cause.

Your port 8091 is already owned by HTTP.SYS (PID 4), not by the Universal Print Connector. That’s why the connector fails with “Failed to initialize authentication” and stops immediately: it cannot register its WCF endpoint.

You can confirm the reservation with:

netsh http show urlacl

Look for an entry containing 8091.

✔️ Fix

Remove the conflicting reservation:

netsh http delete urlacl url=http://+:8091/

Then restart the Universal Print Connector service.

If you prefer, you can also switch the connector to another port, but cleaning the HTTP.SYS reservation is usually the correct fix.

Let me know what netsh http show urlacl returns — that will confirm the exact conflict.