Windows 11 freeze randomly after startup; close internet is ok. What is the cause?

What you’re describing points to a network driver or service conflict that only shows up once the machines are online. When the router is off, Windows boots cleanly, but once the NIC initializes with active connectivity, a process tied to network discovery or endpoint security is hanging the system.

This can be caused by outdated or corrupted network drivers, or by recent Windows updates that changed how certain services (like SMB, DNS client, or endpoint protection agents) interact with the stack.

The best first step is to update the LAN driver from the motherboard or NIC vendor site rather than relying on Windows Update. If the issue persists, check Event Viewer under System for critical errors around the time of the freeze, especially entries from Netwtw, NDIS, or Tcpip. Also confirm that any antivirus or endpoint agent is current, since older builds can lock the system when the network stack comes up.

If multiple machines in different locations show the same behavior, it’s likely tied to a recent Windows patch, so monitoring Microsoft’s release notes and hotfixes is important.

They are different sets of desktop computers both at work and at home