Win Update KB5121767 Windows 11 Out-of-band Update build 26100.8894 (24H2) and 26200.8894 (25H2) - July 18

JGToy · 2026-07-19T01:33:56-0400

It is over...

fg2001gf11F · 2026-07-19T02:23:42-0400

BrianInEngland said:
Not seeing that here, working fine

Did you get the same update of the Windows Security Application?
The machines with the same Build 26200.8894 that still have the older Security Application version do not have the problem.
This one below is also in R.P. with same build 26200.8894 and the older security application and does not have the problem.

BrianInEngland · 2026-07-19T02:25:36-0400

fg2001gf11F said:
Did you get the same update of the Windows Security Application?
The machines with the same Build 26200.8894 that still have the older Security Application version do not have the problem.
This one below does not have the problem.

View attachment 177042

I got this last week

fg2001gf11F · 2026-07-19T02:30:29-0400

BrianInEngland said:
I got this last week

That is the older Security Application, and it still works with the older defender schema.
With the new Security application 29628 they get out of sync with the defender schema and cause the problem.
You can check with Copilot about this issue.

BrianInEngland · 2026-07-19T02:53:47-0400

fg2001gf11F said:
That is the older Security Application, and it still works with the older defender schema.
With the new Security application 29628 they get out of sync with the defender schema and cause the problem.
You can check with Copilot about this issue.

No I got this Security update last week, I'm using Release Preview

fg2001gf11F said:
That is the older Security Application, and it still works with the older defender schema.
With the new Security application 29628 they get out of sync with the defender schema and cause the problem.
You can check with Copilot about this issue.

View attachment 177045

When did you get this update? I've not had it, maybe it was pulled

fg2001gf11F · 2026-07-19T03:07:44-0400

BrianInEngland said:
No I got this Security update last week, I'm using Release Preview

When did you get this update? I've not had it, maybe it was pulled

I got the new security application together with the Build update today on R.P. channel, but only on one machine.
Microsoft is still doing A/B testing with this Security Application; it does not go to all machines.
Copilot can explain what is going on with this mess.

The application needs to match the defender schema used by the specific build. Up to now, they only fixed that problem on build 29617.1000 with the security application 29617.

PurSpyk!! · 2026-07-19T03:28:15-0400

I have this version installed for some reason:

fg2001gf11F · 2026-07-19T04:01:31-0400

PurSpyk!! said:
I have this version installed for some reason:

View attachment 177050

Then you should also get the problem with the wrong notification if you are on R.P. with build 26200.8894 and with that Security Application version

Cameraman1955 · 2026-07-19T04:04:44-0400

PurSpyk!! said:
I have this version installed for some reason:

View attachment 177050

Where can I find this information ?

PurSpyk!! · 2026-07-19T04:15:50-0400

Cameraman1955 said:
Where can I find this information ?

PurSpyk!! · 2026-07-19T04:23:42-0400

fg2001gf11F said:
Then you should also get the problem with the wrong notification if you are on R.P. with build 26200.8894 and with that Security Application version

View attachment 177052

It is annoying that this still has not been fixed, or even acknowledge by MS as an issue

gtspeck · 2026-07-19T08:35:30-0400

I don't have a Dell so I will skip this one.

Globespy · 2026-07-19T09:10:43-0400

Thanks @Brink - I do have optional updates checked, but they say you learn something new every day; I had no idea this option would offer updates that are system agnostic, and as your notes pointed out, it is NOT required for non-Intel based platforms.
Now I wonder whether past PC issues may have been caused by an incorrect assumption on my part that at the very least these optional updates would use some sort of intelligence to know whether they are relevant given my system specs MUST be known to the WU system.
Clearly not.
Is there actually any potential for system issues if I've been installing updates that are not meant for my PC?

Brink · 2026-07-19T09:12:17-0400

Globespy said:
Thanks @Brink - I do have optional updates checked, but they say you learn something new every day; I had no idea this option would offer updates that are system agnostic, and as your notes pointed out, it is NOT required for non-Intel based platforms.
Now I wonder whether past PC issues may have been caused by an incorrect assumption on my part that at the very least these optional updates would use some sort of intelligence to know whether they are relevant given my system specs MUST be known to the WU system.
Clearly not.
Is there actually any potential for system issues if I've been installing updates that are not meant for my PC?

It shouldn't matter. This is just another cumulative update that just happens to include a fix for the Dell issue. If you don't have an affected Dell PC, then the update can be optional, but won't hurt anything if installed.

Josey Wales · 2026-07-19T09:12:23-0400

Globespy said:
Thanks @Brink - I do have optional updates checked, but they say you learn something new every day; I had no idea this option would offer updates that are system agnostic, and as your notes pointed out, it is NOT required for non-Intel based platforms.
Now I wonder whether past PC issues may have been caused by an incorrect assumption on my part that at the very least these optional updates would use some sort of intelligence to know whether they are relevant given my system specs MUST be known to the WU system.
Clearly not.
Is there actually any potential for system issues if I've been installing updates that are not meant for my PC?

I had that setting off on my Wife's NUC , but she got it anyway.

botus · 2026-07-19T10:50:23-0400

Brink said:
It shouldn't matter. This is just another cumulative update that just happens to include a fix for the Dell issue. If you don't have an affected Dell PC, then the update can be optional, but won't hurt anything if installed.

why would they push an out of bound update on to all machines that aren't Dell if it didn't cause issues ?

just before this came out - one of the people I offer my limited support too, had her W11 25H2 fully patched HP laptop boot up asking for the bitlocker key, fortunately she could retrieve and got windows to boot - whereupon it asked for it all over again

we've turned that off now - the only person it does anything for is the owner getting messed about

could some of the fixes in

KB5121767

been related to bitlocker magically messing up your life?

Oh, and on yet another HP machine that just got this update, attachments that are in an email sent twice this morning and then 5 hours later are not turning up on a real version of Outlook 2019 - and trying to view the mail crashes Outlook multiple times - even after a reboot to get KB5121776 fully installed - but they are there on a Dell Win 10 machine running Outlook 2007 and both the body of the mail works and the attachment opens !

dbartenstein · 2026-07-19T10:55:04-0400

I came home form work yestiddy seeing my 'puter wanted a restart from Windows Update. No Dell here; a Lenovo...

Brink · 2026-07-19T11:03:10-0400

botus said:
why would they push an out of bound update on to all machines that aren't Dell if it didn't cause issues ?

just before this came out - one of the people I offer my limited support too, had her W11 25H2 fully patched HP laptop boot up asking for the bitlocker key, fortunately she could retrieve and got windows to boot - whereupon it asked for it all over again

we've turned that off now - the only person it does anything for is the owner getting messed about

could some of the fixes in

KB5121767
been related to bitlocker magically messing up your life?

Oh, and on yet another HP machine that just got this update, attachments that are in the email sent twice this morning are not turning up on a real version of Outlook 2019 - and trying to view the mail crashes Outlook multiple times - even after a reboot to get KB5121776 fully installed - but they are there on a Dell Win 10 machine running Outlook 2007 and both the body of the mail works and the attachment opens !

I find that if it's considered a cumulative update (out-of-band or not), it will usually automatically install even if you have "Get the latest" turned off.

RJF2026 · 2026-07-19T11:04:12-0400

I installed the "KB5121767" patch,
and I DON'T have a Dell computer.
I have a White Box ( Built PC)
MSI mb/AMD CPU.

And there has been a Big Difference in performance
For the better!

And there are NO issues with the patch.
At least for my system.

BrianInEngland · 2026-07-19T12:23:18-0400

Installed here this morning on a system will zero DELL components

Available	Next Step
	This update is an optional update. To install this optional update, go to Settings > Windows Update > Advanced options > Optional updates.
	Before you install this update To get the standalone package(s) for this update, go to the Microsoft Update Catalog website. This KB contains one or more MSU files that require installation in a specific order.

Win Update KB5121767 Windows 11 Out-of-band Update build 26100.8894 (24H2) and 26200.8894 (25H2) - July 18

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