25H2 Logon problems September 2026

[psydii]

This just crossed my radar, not seen anything yet, but not checked either. Thought I'd drop it here in case it's useful for anyone.

 

KB5124008 Is Breaking Domain Logons on Windows 11 25H2 —… — EndpointWeekly

[Olliedawg]

We have KB5124008 installed on 15 local domain joined PC's with a Server 2022 DC, no issues as of yet.

[mikes]

Cached credentials still work so if they are used by the same person you won't see it yet.

Was thinking of deploying this the other day but my policy still holds, I'll never deploy a Windows update until at least 2 weeks have passed.

[ITGuyNW]

We're on WS22 and no issues here.

[DavR]

Yup, verified with our Server 2022 DCs, all seems OK at the moment.

 

I wonder which protocol or whatever it breaks that's in Server 2019, but not 2025? I shut down some of the less secure ones on our Server 2022 DCs a while back.

[mullet_man]

I keep seeing some congratulations of Server 2022, but not sure what? We are on 2022 and seem ok so far on the clients that have updated so far but I've hit pause on Windows Updates so it's only about 10 devices but no one has complained, it could be due to cached credentials though. 

 

If I can find out what specific config of 2022 and if we are ok I'll let them roll out as these latest patches fix a massive amount of security issues.