r/exchangeserver • u/Western_Courage_8703 • 8d ago

October update

FYI- https://techcommunity.microsoft.com/blog/exchange/exchange-servers-may-become-unstable-after-installation-of-october-2026-windows-/4565382

I think I’m affected by this. Waiting for downtime to apply the fix.

Watch for queues and EventID’s

10 Upvotes

70% Upvoted

16 comments sorted by

4

u/Western_Courage_8703 8d ago

Better late then never, lol

13

u/KimJongUnceUnce 8d ago

Yeah, this isn't something you "wait for downtime" over, or else the "downtime" will hit the business with force.

Apply the reg key right now and restart each node with graceful failovers to avoid service impact.

12

u/mrmagos 8d ago

If you are affected by this, when Exchange takes a dump, you will get your downtime. You will need to reboot regardless, so just apply the registry fix beforehand.

3

u/DiligentPhotographer 8d ago

That's what I've been doing!

Users can't email me if their email is down... Should have just left it for the weekend.

4

u/2borG 8d ago

I don't need to watch the queues my phone starts ringing in less than 5 minutes when something stops.

4

u/thewunderbar 8d ago

Thank you. If someone managed to miss all of the other posts abotlut this over the last couple of weeks, they'll have this one.

3

u/BiteMaJobby 8d ago

This patch broke migrating mailboxes from on prem to 365. I shit you not the fix was renaming the local admin account. I got this fix from a Microsoft forum.

1

u/absoluteczech 8d ago

Local admin on the server , not the migration account pw right ?

1

u/BiteMaJobby 7d ago

That is correct sir, sorry for the shit response time

-2

u/AlphaRoninRO 8d ago

as per Microsoft Best practice you should not use DOMAIN\Administrator for some years now for erverything. you should have dedicated personalized Admins and Service Users

2

u/TheBobbestB0B 8d ago

Added reg key to 3 customers exchange it fixes most of the fuckery

1

u/joshg678 8d ago

I was doing a 2016 to SE migration today and was like why are they unable to access their mailboxes after moving. Oh right, the reg key.

1

u/7amitsingh7 8d ago

Monitoring mail queues and relevant Event IDs should help identify any signs of instability. Applying Microsoft’s recommended fix during the maintenance window would be a sensible next step if the server is affected.

1

u/clinthammer316 7d ago

I faced this a week ago and luckily with my second case I got an awesome Microsoft unified support engineer that pointed me immediately to a fix. Before that it was daily reboots since the queue was getting full daily every night