Botched Microsoft update knocks Windows 8, 10 PCs offline – regardless of ISP

A broken software update for Windows 8 and 10 is knackering internet connectivity for users of several ISPs in the UK, Europe and quite likely beyond.

Virgin Media in Blighty is the latest provider to confirm the dodgy code is knocking a number of its customers offline. Proximus in Belgium also says a Windows 10 update is breaking network access.

The problem emerged last week, when BT and Plusnet in the UK admitted that computers running Microsoft's latest patches are losing network connectivity due to what appears to be a problem with their Dynamic Host Configuration Protocol (DHCP) clients.

Essentially, the PCs cannot automatically pick up their LAN-side IP address, router address and DNS settings from their broadband routers, causing them to drop off the internet and disappear from other devices on their network.

This happens regardless of ISP and broadband box, and is understood to be caused by a bad automatically installed Windows Update patch. If you configure your box to use static addresses, you should be OK, or you can run the following the commands to reset the operating system's networking components:

netsh winsock reset catalog
netsh int ipv4 reset reset.log

In a message to subscribers on Sunday, Virgin Media advised that some Windows 10 users were experiencing difficulty connecting to the internet after installing the latest update.

"Microsoft are aware and investigating," it said.

One reader, Adam Comben, got in touch with The Register to report: "We run a retail repair shop and have seen around 25 instances of this since Thursday. It doesn’t matter what ISP or router they’ve been using – we’ve had TalkTalk, BT, Plusnet, Sky, you name it. All with the same problem, they will not obtain an IP via DHCP."

He said the issue is definitely a DHCP problem caused by a broken Windows Update, "although we’ve not been able to identify the cause, it’s an extremely quick fix."

He added: "It’s caused a great deal of disruption for our business customers as it required a site visit for those we couldn’t talk through it on the phone."

The cause of the bug is so far unclear, although Plusnet has blamed an unspecified “third-party update”. The main issue appears to be a recent Windows Update release – but it is hard to tell which one is at fault because Redmond is so secretive about exactly what's inside each upgrade bundle.

The Register has repeatedly asked Microsoft for an explanation. The software giant has remained silent. ®