Win Update KB5121003 Windows 11 Cumulative Update build 26100.9168 (24H2) and 26200.9168 (25H2) - Aug. 11

hader · Monday at 12:55 PM

viatorastrorum said:
"I came across your thread and thought to myself: 'Oh man, I hope I'm not that unlucky, let me check my system real quick.'
BAM!!!! Me too. Joining you all in this 'valley of sorrow' :)"

"
[==========================100.0%==========================] The component store is repairable.
The operation completed successfully.

C:\Windows\System32>dism /online /cleanup-image /restorehealth

Deployment Image Servicing and Management tool
Version: 10.0.26100.8972

Image Version: 10.0.26200.9168

[==========================100.0%==========================]
Error: 0x800f0915

The repair content could not be found anywhere.
Check the internet connectivity or use the "Source" option to specify the location of the files that are required to restore the image. For more information on specifying a source location, see Configure a Windows Repair Source.

C:\Windows\System32>DISM /Online /Cleanup-Image /RestoreHealth /Source:G:\Sources\install.esd "I also ran the command using the /LimitAccess switch."

Deployment Image Servicing and Management tool
Version: 10.0.26100.8972

Image Version: 10.0.26200.9168

[==========================100.0%==========================]
Error: 0x800f0915

The repair content could not be found anywhere.
Check the internet connectivity or use the "Source" option to specify the location of the files that are required to restore the image. For more information on specifying a source location, see Configure a Windows Repair Source.

The DISM log file can be found at C:\WINDOWS\Logs\DISM\dism.log

It looks that something is not correct with your Windows system. Make sure to run SFC /scannow. There may be error that can be fixed with SFC.

I tried the same with my system;

1 - DISM /online /cleanup-image /RestoreHealth -> Completed with no errors.
2 - DISM /Online /Cleanup-Image /RestoreHealth /Source:G:\sources\install.esd /LimitAccess - > Completed with no error

Note: G contains a mounted MCT ISO with build 26200.9168 (Assuming your system is also updated to 26200.8168)
/LimitAccess only say's; Use no internet connection for this. Only local.
I could clearly see in the CBS.log that it found "Corruption". (=false! This is because of that CBS Bug in 8655 that is not fixed.)
1 - Without this switch; because is "sees" corruption again and starts the WUDownload proces.
2 - With the switch it "sees" corruption again but don't start (because of this switch) not the WUDownload proces.
The main difference now between them: time! (1) took some 10 Minutes, and (2) took 1 Minute.

So to be short. If you are at 26200.xxxx and use a MCT 26200.xxxx mounted ISO and your system needs Repair (ScanHealth said so...) Use Option 2!
It should fix isssues.... If not? That simply means that the MCT ISO does not contain everything. It should! But I have no way to test this because my system does not need fixing.

gunrunnerjohn · Monday at 1:25 PM

hader said:
It looks that something is not correct with your Windows system. Make sure to run SFC /scannow. There may be error that can be fixed with SFC.

I tried the same with my system;

1 - DISM /online /cleanup-image /RestoreHealth -> Completed with no errors.
2 - DISM /Online /Cleanup-Image /RestoreHealth /Source:G:\sources\install.esd /LimitAccess - > Completed with no error

Note: G contains a mounted MCT ISO with build 26200.9168 (Assuming your system is also updated to 26200.8168)
/LimitAccess only say's; Use no internet connection for this. Only local.
I could clearly see in the CBS.log that it found "Corruption". (=false! This is because of that CBS Bug in 8566 that is not fixed.)
1 - Without this switch; because is "sees" corruption again and starts the WUDownload proces.
2 - With the switch it "sees" corruption again but don't start (because of this switch) not the WUDownload proces.
The main difference now between them: time! (1) took some 10 Minutes, and (2) took 1 Minute.

So to be short. If you are at 26200.xxxx and use a MCT 26200.xxxx mounted ISO and your system needs Repair (ScanHealth said so...) Use Option 2!
It should fix isssues.... If not? That simply means that the MCT ISO does not contain everything. It should! But I have no way to test this because my system does not need fixing.

SFC runs clean on my system. I don't think there is anything wrong with the running Windows or the component store.

BTW, option two fails on my system in exactly the same way with the same error as have all my other attempts with several different ISO files and on-line sources.

hader · Monday at 1:44 PM

OK. I must confess. I am a technerd.

I talked to ChatGTP about this CBS-bug inside 8655 and onwards.
Got some surprising insight about the issue: (Was always wondering why RestoreHealth made 2 attempts to download 256Mb. 1st: 256Mb. 2nd: 0 Bytes...)

Since build 8655, the CBS engine has developed a faulty "loop" in its online payload verification routine:

1. The false trigger: As soon as `/RestoreHealth` is invoked, the engine forces an online check. Due to an error in metadata parsing, the engine incorrectly assumes something is missing locally, regardless of the component store's actual status.

2. The 2x 256MB download bug: The engine connects to Windows Update and downloads a cached metadata/repair index of exactly ~256MB. Because the bug prevents the parser from correctly updating the local database after the initial download, it immediately triggers a second attempt (the "retry loop"). This second attempt results in a 0-byte transfer because the server recognizes that the client already possesses the file; however, the DISM client continues to wait for a timeout for several minutes.

3. The time wasted: This explains exactly why your operation's duration increased from 4 minutes to 14 minutes. On slower systems—or those with slower disk or network connections—this indeed causes the process to get stuck at the notorious "62.3% or 100%" mark for up to an hour, even though the CBS.log subsequently reports that zero corruptions were found.

I now see why that second attempt fails. The server "thinks" 'You got it already! Why asking for it again? I refuse to give you that download of 256Mb'
That is basically 2 is saying! You can find clues inside the CBS-log and only keeps on downloading 256Mb because it "suspects" something. You can see that it makes always the wrong decision now that "something" is corrupt and needs to download stuff in order to repair things. In the end it repairs nothing! The final report further on in the CBS.log show that nothing has been repaired. See attachment.

OK. Now to see and measure how long things take. 3 tests. (Don't look at the time. This is the time with my fast system and fast disks. It gives you an idea! By executing ScanHealth and the time it took to complete this task (From TI init till TI finish - 2 minutes) you got a factor which you can use to check how long it takes in 1,2 and 3.)

Test. Repeat 3x times:
1 - DISM /Online /Cleanup-Image /RestoreHealth

Code:

Start: 2026-08-17 17:57:18, Info                  CBS    TI: --- Initializing Trusted Installer ---
End  : 2026-08-17 18:10:05, Info                  CBS    Ending TrustedInstaller finalization.            <Including shuting down the TrustedInstaller. Autoshutdown after 2 min>
Time : 00:10:47. (ex-Timeout)
Download: 256MB
Retry Download: 0 Bytes (Server says: You just download this one; I am not doing it again…)

2 - DISM /Online /Cleanup-Image /RestoreHealth /Source:G:\sources\install.esd

Code:

Start: 2026-08-17 17:36:14, Info                  CBS    TI: --- Initializing Trusted Installer ---
End  : 2026-08-17 17:48:43, Info                  CBS    Ending TrustedInstaller finalization.            <Including shuting down The TrustedInstaller. Autoshutdown after 2 min>
Time : 00:10:29. (ex-Timeout)
Download: 256MB
Retry Download: 0 Bytes (Server says: You just download this one; I am not doing it again…)

3 - DISM /Online /Cleanup-Image /RestoreHealth /Source:G:\sources\install.esd /LimitAccess

Code:

Start: 2026-08-17 18:30:27, Info                  CBS    TI: --- Initializing Trusted Installer ---
End  : 2026-08-17 18:33:18, Info                  CBS    Ending TrustedInstaller finalization.            <Including shuting down The TrustedInstaller. Autoshutdown after 2 min>
Time : 00:00:51.  (ex-Timeout)
Download: Nothing

I could see that with the /LimitAccess it prohibits to download from the MS-Download server: CBS Repr: The system configuration is not qualified for Windows Update download, skip WU.

For comparison: I looked at the duration of ScanHealth

Code:

Start: 2026-08-17 18:37:56, Info                  CBS    TI: --- Initializing Trusted Installer ---
End:   2026-08-17 18:40:48, Info                  CBS    Ending TrustedInstaller finalization.            <Including shuting down The TrustedInstaller. Autoshutdown after 2 min>
Time : 00:00:52. (ex-Timeout)

To bypass this issue; Use test option 3.
G is a mounted drive wich contains a MCT ISO of 26200.9168. (Reflects the build my system has)
In theory it should fix anny issues also without downloading anything. It then must use the content of that MCT ISO 26200.9168.
I have now no way to test this (My WIndows system is not broken)

But if anybody sees that ScanHealth gives you the order to execute RestoreHealth. Try option 3. Downside is that you must download a MCT ISO with the correct build of your system. So use ScanHealth first, then use option 3.

Hope I shed some light and found a way around this CBS-Bug.... Let me know if someone that needed that option 3 it fixed the problem inside Windows by repairing stuff using the MCT ISO as source instead of downloading each time.....

gunrunnerjohn · Monday at 2:02 PM

hader said:
But if anybody sees that ScanHealth gives you the order to execute RestoreHealth. Try option 3. Downside is that you must download a MCT ISO with the correct build of your system. So use ScanHealth first, then use option 3.

Hope I shed some light and found a way around this CBS-Bug.... Let me know if someone that needed that option 3 it fixed the problem inside Windows by repairing stuff using the MCT ISO as source instead of downloading each time.....

DISM /Online /Cleanup-Image /RestoreHealth /Source:G:\sources\install.esd /LimitAccess won't work as the index is 6 for the MCT downloaded ISO.

Did you look at my previous post?

DISM /Online /Cleanup-Image /RestoreHealth /Source:I:\sources\install.esd:6 /LimitAccess is the proper command for the MCT ISO if you're running Win11 Pro. That one fails.

Just for fun, I ran your exact command, just changing the drive letter where the ISO was mounted. It fails the same way.

hader · Monday at 2:12 PM

gunrunnerjohn said:
SFC runs clean on my system. I don't think there is anything wrong with the running Windows or the component store.

BTW, option two fails on my system in exactly the same way with the same error as have all my other attempts with several different ISO files and on-line sources.

View attachment 179932

Can you repeat this without the index; ':6'?
It is not needed with this command. If the .ISO matched your build it should contain the version you have; Home, Pro etc.
I use this index only if I want to know something about the build of an ISO;

Code:

Dism /Get-WimInfo /WimFile:G:\Sources\install.esd /index:5

For my language version (Dutch) I must use index 5, but if you are using the US version it is 6.

Does the ISO matches with the build of your current system? (If 26200.9168, use the MCT version now downloadable with 26200.9168)
If they don't match such an error like 0x800f0915 is to be expected; It could not find the things it needed to repair your system.

If you use the current version of the MCT ISO: 26200.9168 and this is not repairing stuff because it could not find things?
Oeps!! Then there must be:
1 - That MCT ISO does not contain all items of 26200.9168. That would be a huge mistake on the part of Microsoft.
2 - Your system is broken and can not be fixed.

Note: Personally I have met situation 2. I could not resolve the issue whatsoever. Tried everything! The only way I could fix this issue was to start an In-Place-Installment. Never seen this situation since... I suspect this is the case also with you because the same error occurred with the online repair with just /RestoreHealth alone. In you case it give the same error. That is an serious issue. As well online and offline. Both are failing with the same error. It can not be fixed by this way. If you want to fix it; you need to run an In-Place-Installment also.... I am afraid.

I have seen similar issues at other people. They could not fix it either. An In-Place-Installment resolved in the end all cases. It's a better option then doing a fresh install....

gunrunnerjohn · Monday at 2:19 PM

hader said:
Can you repeat this without the index; ':6'?
It is not needed with this command. If the .ISO matched your build it should contain the version you have; Home, Pro etc.

Did you look at my previous post? I ran it with and without the index specification. The second image is without the index specification.

cute two · Monday at 2:32 PM

Is there problem with install Windows with MCT of 26200.9168 ? I don't want to make FORMAT and then stuck without Windows.
I always do format when install windows.

gunrunnerjohn · Monday at 2:35 PM

cute two said:
Is there problem with install Windows with MCT of 26200.9168 ? I don't want to make FORMAT and then stuck without Windows.
I always do format when install windows.

Don't know, I haven't installed it from scratch. I will say that I have three other machines running 26200.9168 and none of them have this problem, so it's not totally bad.

hader · Monday at 2:54 PM

gunrunnerjohn said:
....

Just for fun, I ran your exact command, just changing the drive letter where the ISO was mounted. It fails the same way.

Yeah. That means: In-Place-Installment! The issue can not be fixed by this way.
Just mount the MCT ISO and execute setup.exe. It already knows you are doing an In-Place-Installment without touching your data. Have done this many time when I had things that I could not resolve.

Once I created a Windows Sandbox and tweaked in such a way that from a blank and fresh start; it always altered some registry-keys and installed local programs that I always uses. So that I don't have to repeat this proces each time I started the Sandbox. Once started my desktop and background was already set in the way I liked it to be and all programs that I wanted were already installed. Made a paper "How to..." Not very complicated. You have to adjust some files that Sandbox is using when it starts. Otherwise by default you start withe an empty Sandbox: Standard and plain.....
Until...... Something broke without any warning or changes that I made! Sandbox was corrupted. Looked in al container directory's, logfiles for a clue: Nothing.
Could not fix this issue. So... Deleted the Sandbox and de-install that option from Windows by turning off (inside) the feature section: Windows Sandbox.
Reboot. Was busy turning things off.. Then. Oeps! Something went wrong (what then??) Revert to the old situation. With that broken sandbox.
Could not be fixed! Had to execute an In-Place-Installment to fix everything.

So that was my Sandbox adventure. Since then I never used this untrustworthy option from MS. I went back to VMWare and Oracle Box for every VM.
I find it totally unnecessary if you install Windows Pro it automatically installs many Hyper-V or Hypervisor service without ever using them. Those service should be installed if you turn on Windows Sandbox because it needs them in order to run a Sandbox. (or a MS VM)
It is wrong to install Hyper-V along with Windows Pro. It should be something you can install just like VMWare and Oracle. If something goes wrong? Deinstalling and reinstalling fixes the issue. Now with Hyper-V I had to re-install Windows again without touching my personal data. Installing a product and deinstalling it takes a couple of seconds. Reinstalling Windows and leaving my data alone? Take many many minutes.....

gunrunnerjohn · Monday at 3:03 PM

hader said:
Yeah. That means: In-Place-Installment! The issue can not be fixed by this way.
Just mount the MCT ISO and execute setup.exe. It already knows you are doing an In-Place-Installment without touching your data. Have done this many time when I had things that I could not resolve.

Been there, done that, three times! Once with the on-line source, once with a UUP ISO, and once with the same version MCT ISO. In all cases the repair completed without error and "apparently" worked fine. However, when I check the system with DISM RestoreHealth run, I get the same error about can't find the files anywhere. Been down all those rabbit holes...

SFC /SCANNOW runs without error on the system, which leads me to believe this is not a problem with the component store but rather with the registry. The component store is completely replaced when you do a repair install, so it's unlikely it's really corrupt. The fact that SFC finds no problems also suggests that the component store is intact.

PurSpyk!! · Monday at 4:50 PM

I believe if your system is stable dont worry about this, we are going around in circles, and nothing seems to fix this mess. I would assume only MS can fix this. I have systems with this issue, and others don't, so it seems random, or an accumulation of issues that are now only showing up. I never used to worry about checking my system after each build, and I will revert to that behaviour from now on.

gunrunnerjohn · Monday at 5:17 PM

PurSpyk!! said:
I believe if your system is stable dont worry about this, we are going around in circles, and nothing seems to fix this mess. I would assume only MS can fix this. I have systems with this issue, and others don't, so it seems random, or an accumulation of issues that are now only showing up. I never used to worry about checking my system after each build, and I will revert to that behaviour from now on.

I believe you're right, I've already made that decision. After all, most Windows users don't know anything about DISM or SFC, and they run for years in happy ignorance!

It seems pretty clear if this gets fixed, it'll be Microsoft fixing it. Since it's happened to a bunch of people, sooner or later the root cause should surface.

hader · Monday at 5:36 PM

cute two said:
Is there problem with install Windows with MCT of 26200.9168 ? I don't want to make FORMAT and then stuck without Windows.
I always do format when install windows.

It does not matter if you format things. With format you just reformat your drive to make sure that no corrupted sectors are left.
You have to format your disk once. Once you bought a disk. They are already lowlevel formatted but despite this it is a good thing to do. And then you are most likely not formatting the whole disk!! but only use quickformat. That will generate a new MBR/GPT index table. (with where the start of a files can be found on which sector on your disk. If you want you to change the sector size or switch from an other format to NTFS.

Nowadays with SSD's and NVMe's there is not need to format stuff. They have a MTBF of approximate 1,5 million hours. You can drop these devices without consequence. With HDD that is a different story. When you bump you system hard enough; the read/write head can touch the disk surface cause bad sectors. Those will be marked inside the MBR/GPT table; Never use these sectors. Done by running chkdsk.

By rule if chkdsk finds no bad or damaged sectors; there is no nee to reformat them. With SSD's and NMVe's even more. Data is not stored in a magnetic surface like HHD's. They are flashed inside silicon. (bits 0/1)

Sometime you need to reformat disks if you change the partition side. But if the size remains as they are; no formatting is needed (If chkdsk find no errors)
And even in the case of resizing of partitions; Some partition software can change it size without formatting. Windows has limited function on that area once. But could be also done by diskpart or partition magic but there must be some unallocated space somewhere. Yu can expand beyond it physical borders. At the moment Windows uses 3 partitions by default
1- EFI partition, size 200Mb, FAT32, Marked: System. (Hidden)
2- C-Drive partition size remainder of the diskspace minus EFI and WinRE, Marked: Boot. (C-Drive)
3- WinRE partition, size 876MB, NTFS, Marked: Hidden. (Hidden)

The EFI takes up 200Mb but it's filled for 10% (40Mb). Some people resizes it to 50Mb. They add the free space to the C-drive. Not a good thing. In practice it should not be sized lower then 100Mb. I have seen case where updates failed because the content of the EFI partitions exceeded 50Mb. In order to resolve that situation they deleted some language files on that EFI-partition. A stupid thing to do!

So complete formatting it not really necessary unless there are bad sectors on you disk. During this complete format it will see those bad sectors and mark the sector(s) as unavailable inside the MBR/GPT index table. (From then on no data is stored on these bad sectors)

When you install for the first time Windows. Windows (if it sees unallocated space) makes those 3 partitons. Does a quickformat (it assumes that the disks already has been formatted by the disk manufactory when new) to make new MBR/GPT index tables. There is an option to do a complete format if you want but because it must format the complete disk it takes up much more time than a quickformat. Never used this option! Not needed also.

When re-installing Windows from scratch it sees those previous made partitions and just quickformats the drive. Any data left in those sectors from the previous installment are lost forever because en empty MBR/GPT index table is made at the start of the drive. This is always the case and the number of sectors is also the reason why you have a e.a. 250Gb disk (Manufactor thinks 1Gb = 1.000.000.000 Bytes. *1K=1000 Bytes* Windows thinks 1Gb = 1.073.741.824 Bytes *1K =1024 Bytes*) So 238Gb left. So where is my 12GB of missing space gone!?!
1 - Windows calculates diskspace in 1024 in stead of 1000.
2 - The MBR/GPT takes up only some (Windows is saying my 250Gb drive is 231Gb in size. 250Gb-231Gb=19Gb but 250Gb-238Gb=12Gb. So 19-12=) 7Gb (The MBR/GPT index table space takes up only a couple of 100Mb of space. The rest is reserved for expansion. When you have 10 biljoen of small files; that reserved of 6Gb will fill quickly) Because of these two factors the disk seems to be smaller in size than advertised. Linux does not have that 1000/1024 issue. Only Windows does.

So far some basics... With large TB HDD's a complete highlevel format can take up to one hour or more. By lowlevel formatting by the manufactory as a service this highlevel formatting can be skipped. Windows is not capable of doing a lowlevel format only highlevel formatting. Especially with SSD's and NMVe's you !never! need to do a highlevel format because a quickformat is always sufficient.

lowlevel format: Only done by the disk manufacturer.
highlevel format: Generate a new MBR/GPT index table. Writes zero into each sector and checks for bad sectors. Those will be marked in the MBR/GPT index table.
quickformat: Only writes a new MBR/GPT index table. chkdsk will check for bad sectors and mark them in the MBR/GPT table.

Wannagofast · Monday at 7:17 PM

cute two said:
Is there problem with install Windows with MCT of 26200.9168 ? I don't want to make FORMAT and then stuck without Windows.
I always do format when install windows.

There is no problem with MCT of 26200.9168. I did a clean install with it yesterday and everything worked fine.
Used MCT to download the ISO and Rufus to create the USB so I could easily skip the MS account during install.

peace
wanna

fg2001gf11F · Monday at 7:45 PM

Wannagofast said:
There is no problem with MCT of 26200.9168. I did a clean install with it yesterday and everything worked fine.
Used MCT to download the ISO and Rufus to create the USB so I could easily skip the MS account during install.

peace
wanna

You did not check "Repair my PC" that one still has a bug.
It reboots the main OS instead of showing the recovery menus.

garlin · Monday at 8:34 PM

Confirmed as broken.

Code:

Drive D: "ESD-USB"
    Boot File [Production PCA 2011] is BANNED.
        D:\EFI\Boot\bootx64.efi
        File Version: 28000.352, SVN 9.0

    boot.wim:2 (WinPE 26100.9168)
        Boot Manager [Windows UEFI CA 2023] is ALLOWED.
            \Windows\Boot\EFI_EX\bootmgfw_EX.efi
            File Version: 28000.352, SVN 9.0

        \Windows\System32\winload.efi is ALLOWED.
            File Version: 26100.9168

        'Repair My PC' is broken in WinPE.

gunrunnerjohn · Monday at 8:39 PM

If only that were the only thing broken...

PerpetualCycle · Monday at 8:46 PM

gunrunnerjohn said:
If only that were the only thing broken...

Doesn't look good for the commitment to quality right now.

TraderGary · Monday at 8:48 PM

gunrunnerjohn said:
If only that were the only thing broken...

Are you kidding? I see this update had 421 fixes! :what:

PurSpyk!! · Monday at 9:49 PM

TraderGary said:
Are you kidding? I see this update had 421 fixes!

I hope all these AI detected bugs get verififed before code gets changed, otherwise we could lade up in a real mess.

Available	Next Step
	This update downloads and installs automatically from Windows Update and Microsoft Update.
	To install this release from the Microsoft Update Catalog, select the option that matches your device architecture (arm64 or x64), and then follow the instructions.

Win Update KB5121003 Windows 11 Cumulative Update build 26100.9168 (24H2) and 26200.9168 (25H2) - Aug. 11

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