Windows 11 upgrades are supposed to be boring. You click update, it restarts a few times, and you get back to work. But for a small group of users, the experience has reportedly been the exact opposite: upgrade completes, Windows loads… and suddenly the machine can't get online through Ethernet.

And the most frustrating part is how specific (and repeatable) the issue sounds.

The Complaint: Ethernet Stops Working After An Upgrade

A user who upgraded from Windows 11 23H2 to 25H2 says their Dot3Svc folder was wiped during the upgrade process. That matters because Dot3Svc is tied to wired 802.1X authentication, which is commonly used in workplaces that rely on Network Access Control (NAC).

When those policies and settings vanish, wired authentication fails, and the device can't reconnect to the network through Ethernet. In plain English: the PC boots fine, but it's effectively offline in an environment where 802.1X is required.

What Dot3Svc Actually Does

Dot3Svc is short for Windows Wired Auto Config, a built-in Windows service that handles IEEE 802.1X authentication on wired (Ethernet) connections. If your organization uses 802.1X for wired access (which is common in managed networks), Windows needs those policies to authenticate before the network will let you in.

So when the Dot3Svc folder gets cleared or corrupted, Windows isn't just "having a network hiccup." It's missing the credentials and policy rules it needs to pass the network's access checks.

Why People Say This Issue Has Been "Plaguing" Upgrades

The user's point is that this isn't a brand-new bug. Similar reports have been floating around since earlier Windows 11 upgrade paths, including in-place upgrades from Windows 10 to Windows 11, and some users also associated it with Windows 11 24H2 and 23H2-era upgrade cycles.

That's why it feels extra irritating: you can follow Microsoft's preferred path (upgrade to Windows 11, stay current), and then lose the exact thing Microsoft insists you have during setup… an internet connection.

The Catch: No Clear Public Acknowledgement

Based on what's being discussed online, the issue seems to have shown up in multiple community threads, but it wasn't something Microsoft clearly called out on the Windows health dashboard (at least publicly, in a way most admins would easily spot).

There were also claims that patches around late 2024 (specifically November and December Patch Tuesday updates) addressed the problem for some people, but users are still reporting cases where it shows up again with later upgrades.

In other words, even if it was "fixed" once, it doesn't feel fully dead.

The Only Fix People Keep Coming Back To

The workaround being shared is simple, but also kind of ridiculous if your situation is wired-only:

Once Group Policy pulls down the correct settings again, Ethernet authentication can start working normally.

The annoying part is obvious: if you're in a locked-down environment where Wi-Fi isn't available, getting that first connection back can be the hardest step.

Who Should Care About This

If you're a typical home user, you'll probably never notice because most home networks don't use 802.1X for Ethernet authentication.

But if you're in a business, hospital, school, or any managed environment where wired 802.1X is enforced, this is exactly the kind of upgrade bug that turns into a helpdesk flood. One upgrade wave can suddenly create a pile of "my PC has no internet" tickets, even though the cable, switch port, and network are all fine.

Final Thoughts

This is one of those issues that sounds almost like a joke until you've lived through it: an upgrade finishes successfully, but it quietly removes the policies that allow the computer onto the wired network.

If the reports are accurate, the real pain isn't just the bug itself. It's that the fix depends on already having some other way to get online so you can pull Group Policy back down. For environments that depend on wired NAC, that's not just inconvenient, it's disruptive.

If you want, paste the exact folder path you're using and whether the PCs are domain-joined or Intune-managed, and I'll rewrite this as a tighter admin-focused advisory you can share internally.