7 Days of Frustration. Windows 11 – Packet loss immediately after uninstalling SEP

[MRRatcliffe]

Hi everyone,

I'm seeing a repeatable issue on multiple Windows 11 PCs.

As soon as Symantec Endpoint Protection is uninstalled, intermittent packet loss begins (roughly every 80 seconds). Reinstalling SEP immediately restores stable networking.

I've already tried:

• CleanWipe
• Winsock/TCP-IP reset
• Windows Firewall reset
• Updated NIC drivers
• Different NICs, switches and networks
• Checked for remaining Symantec drivers, bindings and WFP entries

Has anyone seen SEP leave behind any networking components after uninstall, or know of any advanced diagnostics that could identify what is changing?

Any ideas would be appreciated.

[MRRatcliffe]

There is only 1 PC where we have managed to removed SEP and the TCP connections don't drop out. Anything that could be causing this PC to work correctly?

I removed SEP on all the machines using standard add/remove programs.

Thanks