Bypass ESU Blue

I said nothing about those LCUs. I only said KB5062597 was incompatible. What's wrong about that?

For me, if this was intentional from Microsoft, then it is indeed Game Over for Windows 8.1 x64 as in it will no longer be possible to install future security updates on it.

 

Perhaps Microsoft removed those packages from the update and found Windows 8.1 would not boot and decided to go ahead as a way to punish those who insists on installing the update on Windows 8.1?

Seriously, I agree with you that Microsoft should have blocked users from installing the update on Windows 8.1 if it does not want users to use them on 8.1. So what is Microsoft thinking here? And why do it now and not earlier?

 

No one stops you from copying the updated files from a 2012 R2 install. The problem then becomes figuring out which ones cause issues.

 

Here's a temporary workaround to install 2025-07 LCUs on Windows 8.x. That is to say, modify the <parent> nodes.

I've made a list of contents that need to be copied to the <parent> section in the .mum files.
(Now available for Windows 8.x (Both 8.0 and 8.1))
(Now only available for the following Languages: en-US & zh-CN.)
The file is appended as an attatchment. THIS WORKAROUND is tested to install successfully on Windows 8.0 Professional and Windows Embedded Standard 8.0 & Windows Embedded Industry Enterprise 8.1.

All the <parent> infos are fetched by the previously released official updates.

In the text file you download,

pNNN -> the number of the LCU's standalone .mum file.
e.g. p100 -> package_100_for_KB......

e.g.

Spoiler: Steps

p100: Microsoft-Windows-WOW64-Windows (amd64)

<assemblyIdentity name="Microsoft-Windows-Client-Features-Package-AutoMerged-windows" language="neutral" version="6.3.9600.16384" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" buildType="release" />

Means:

You need to check if "amd64" version of "Microsoft-Windows-WOW64-Windows" exists in the package_100_for_KB*.mum.
If it exists, then open the corresponding .mum file within any types of the code editors, append the <assemblyIdentity*> contents into the lines between <parent buildCompare="EQ" integrate="separate" disposition="detect"> and </parent>.

HOW TO DO:

Spoiler

1. Download and extract the LCU file.
2. According to which system and language you are using, follow the steps above to modify the .mum files.
3. Use Dism /add-packagepath to install. (just stick to the update.mum file.)

Notice:

Spoiler: Notice

1. After installing the LCU released later than 2025-06, you may experience the client drivers have been downgraded.
To solve this, reinstall the 2025-06 LCU and perform a restart.
2. Some of the server-only assemblies (Not including ESU Licenses for server & Server 2012 EOS Notify) will be installed with the latest LCU. This won't affect your Windows experience.

 

Another question is, how can I generate a .cab file that can not only hold more than 65535 files or 2GB of data archive ,but also keep the folder structure?
I have tried using cabarc commands, but the LCU file is too huge that cabarc reports:
Data-size or file-count exceeded CAB format limits

 

After installing of kb5062597-x64 and getting error code 0x00000100 reverting pending actions was useful
see wintips.org/fix-windows-cannot-boot-after-installing-updates-windows-7-8-10/
(Method 1. Revert Pending Actions by running the DISM tool in WinRE)

 

That's a good idea, but I don't know how to create a installable LCU .cab file with multiple chained .cab files inside.

 

Hello,

I still have that theory that somebody at Microsoft screwed up willingly or unwillingly. Actually, I needed to google that term, and I am not a lawyer either. See: https://forums.mydigitallife.net/posts/1884442

But how would the installation succeed? As far as I know, the MUMs are signed by the CATs.

You can generate a different file type, so long the folder structure is kept, and install from a folder, after extracting an archive's contents.

Cool stuff

Never

I believe that we could come up with some scripts to modify the official Microsoft files in a way:

Extract the official contents; Modify them on the fly; Install them using the deprecated pkgmgr or DISM.

If we can override the signature requirement.

My two cents. Thank you.

 

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Yeah, maybe. But I do not have the time or technical expertise to figure out which ones cause issues.

So for me, if next month's cumulative update for 2012 R2 still causes the same issues on 8.1 x64, then it is game over for Windows 8.1 x64 at least in terms of security update support (not that I am too concerned since I replaced my Windows 8.1 installation with 2012 R2 on my main computer some time ago).

Of course, losing security update support does not mean I will give it up. I still run Windows 7 x64 and Windows 8.1 x64 (both patched to January 2023) on one of my old computers (P67 motherboard) and they will stay there.

 

Don't think so as I've never heard CSA being available for Windows after XP, and also now we have ESU together with Grandfathered Premium Assurance for 2008 Rx (Vista and 7).

 

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on the other hand windows server 2012 r2 it is. until October 2029 via ESU (premium assurance) Azure Arc Private and Windows 8 and 8.1 will no longer have access to the ESU bypass after october 2026

 

You mean there is Premium Assurance available for 2012r2 until October 2029?

 

I also thought there was until I knew it got canceled. Abbodi said there will not be any, so support until Oct 2026.