Windows 11 attempt to upgrade to KB5121003 (26200.9168) was a horrible failure!

Windows update shows I have 2 updates to install, one being KB5121003 (26200.9168). I tried to do this the first time by taking no pre-prep steps. That is to say, I just expected it work. It didn't work. It failed and in the process wasted my good time. If there's one thing I can't stand about the Windows update process it's how long it can linger on a random "percentage completed" value. What becomes the purpose of telling me that something is 66% done, or 92% done if it lingers and lingers and lingers on that same percentage value for ridiculously long amounts of time? It loses value, it loses purpose. The twirling circle is nice. It shows me exactly 1 thing, that my PC hasn't literally frozen up. That's it. The update process need improved and advanced visual feedback. I wanna see what files are being copied, what transactions are taking place. Microsoft could do this by simply adding a checkbox with text on the update screen "Click the box to see details about the update process".

So my first failure there was no research done to prevent failure. For my second attempt I did research. I used dism.exe to clean up and restore image health. I stopped the "Windows Update" service. I stopped the "Bits" service. I stopped "Cryptographic" service. I renamed "SoftwareDistribution" by appending .old to the folder name. I renamed "System32/catroo2" by appending .old to the name.

And tried again. After lots of wasted time and watching the twirling circle go for ages stuck at XX percentage. It failed a second time.

The next advice given by my research was to literally use the Media Creation Tool and download the latest version of Windows. And then to perform an in place upgrade from the USB flash drive. I tried this. For the 3rd time, it fails.

The only good thing I can say about Microsoft's horrible, amateurish sloppy upgrade routines are that after 3 failures it did put my system back to where I first began. I'm up and running on the same version I was prior to Windows wasting 3 or 4 hours of my precious time.

I'm not asking for help, really to get around this. This is an FYI, a rant, a complaint about how XXXXX this attempted upgrade experience was. And how Microsoft could do things so much better. But probably never will. But I do still have hope which is why I write this post.

Take it with a grain of salt but here is what Co-Pilot says about your error:

Most of the time when Windows Setup fails in the SECOND_BOOT phase during MIGRATE_DATA (0x8007042B – 0x4000D), it isn’t the update itself that’s broken — it’s something in the user’s profile or data migration path that Setup can’t process.

Here’s the concise, expert‑level breakdown:

The cause is almost always corrupted, locked, or incompatible user‑profile data that Windows can’t migrate during the upgrade. SECOND_BOOT is the phase where Windows reboots into the upgrade environment and begins copying user data, apps, and settings into the new OS image. MIGRATE_DATA is specifically the step where it tries to move user profiles.

The most common triggers are:

• A corrupted user profile (NTUSER.DAT, registry hive issues, profile service errors)
• Third‑party antivirus or endpoint protection locking files during migration
• Sysprep‑like modifications, redirected folders, or nonstandard profile locations
• Pending file operations or services that refuse to stop
• Broken Windows Update components or partially‑installed updates
• Disk errors in the user profile area (bad sectors, failing SSD/HDD)

Because MIGRATE_DATA only touches user data, this error almost never comes from drivers, TPM, Secure Boot, or hardware compatibility.

Also:

For KB5121003 (build 26200.9168) specifically, the 0x8007042B – 0x4000D SECOND_BOOT / MIGRATE_DATA failure almost always points to one thing:

Something in the user’s profile cannot be migrated during the upgrade to 26200.9168.

And with this particular update, there are two very common triggers seen in the field:

1. Corrupted or non‑standard user profile data​

This update performs a heavier‑than‑usual migration of profile data because it’s part of the Windows 11 Release Preview → 26200 platform transition.If any of the following are true, MIGRATE_DATA breaks:

• NTUSER.DAT corruption
• Redirected Documents/Desktop/Pictures to OneDrive with inconsistent folder states
• Third‑party AV locking profile hives
• Profiles stored on another drive or moved via unsupported methods
• Broken symlinks inside AppData or Documents

This is the #1 cause of SECOND_BOOT failures on 26200.x builds.

2. OneDrive folder‑redirection inconsistencies​

This update is notorious for failing when:

• “Documents” or “Pictures” are redirected but partially unsynced
• The user has duplicate OneDrive folders (e.g., “Documents” and “Documents 1”)
• Files are mid‑sync during upgrade
• Known Folder Move was previously interrupted

This is the #2 most common cause for this specific update.

Why this update triggers it more often​

KB5121003 includes the new migration logic for the 26200 platform, which touches more user‑profile data than typical cumulative updates.Anything unusual in the profile becomes a hard stop.

You're railing that it's all Microsoft's fault when neither the web or this forum have been bombarded with complaints about that update. I updated 4 systems last night without a hitch.

Are you running any third‑party antivirus, VPN, or system‑tuning utilities on this machine?
Those are the most common culprits for 0x8007042B – 0x4000D.

Things to try when windows update fails:

1. Run troubleshooter-settings-system-troubleshoot-other troubleshooters-windows update-RUN.

2. Reset Windows update using Brink's tutorial Reset Windows Update in Windows 11 Tutorial

3. Open command prompt as administrator. Enter this command.
dism /online /cleanup-image /restorehealth
When complete, Restart computer

Then open command prompt as admin again and run sfc /scannow
Pay attention to the scan results to see if SFC found anything it could not repair

4. CLEAN UP COMPONENT STORE - dism /online /cleanup-image /startcomponentcleanup
Analyze and Clean Up Component Store (WinSxS folder) in Windows 11 Tutorial

5. Try to apply the update in clean boot state. Perform a Clean Boot in Windows 11 to Troubleshoot Software Conflicts

6. Try to directly apply the msu by downloading from here. Microsoft Update Catalog

Thank You all for your very kind and helpful replies. And yes, I do still blame some of this failure on Microsoft because it seems like Microsoft could have checked for these issues from the very beginning. Why take the time to install a brand new version of an operating system from scratch. And then revert everything back to how it was prior to this update because you can't migrate one file/folder/application to the new version? Hell, I could have lived with that. Just let it be and I could go in afterwards and migrate what failed to move over. It's just so ridiculous to revert everything after so much investment of time.

@glasskuter I actually did perform step #3 in your recommendations above. I forgot to execute step #4 (unnumbered above). But let's be honest. Would that have helped given this is a failure to migrate user data? Probably not.

I'm very frustrated right now but at least I can take a break and go back and try a smarter way when I have had time to reset, myself, not Windows. You know what I mean.

Yep. When one gets mad or frustrated he should walk away and get some chill time. It will still be there when you settle yourself and come back to it.

JaQuille said:

actually did perform step #3 in your recommendations above. I forgot to execute step #4 (unnumbered above). But let's be honest. Would that have helped given this is a failure to migrate user data? Probably not.

Click to expand...

If the issue is indeed corrupted user data, then no. I ran into that when I upgraded from 24h2 to 25h2. I ended up clean installing which turned out to be a good thing since I had a lot of stuff over the years I did not need.

You run DISM (Deployment Image Servicing and Management) before running SFC (System File Checker) because DISM repairs the underlying system image and component store, which SFC relies on for healthy backup files. If the component store is broken, SFC cannot fix damaged operating system files. SFC is what actually repairs any active corrupted OS files.

Let me point out one thing. Everyone keeps calling this an upgrade. KB5121003 Is a windows update, not an upgrade. It only became an upgrade when you downloaded the iso and did a repair install. I'm curious if that failure you listed came from the failed update or if it was when you used the iso to do a repair install (ie: otherwise known as an inplace upgrade).

I've got to say the 'MIGRATE_DATA' has gotten me more than once.

JaQuille said:

And then to perform an in place upgrade from the USB flash drive. I tried this. For the 3rd time, it fails.

The only good thing I can say about Microsoft's horrible, amateurish sloppy upgrade routines are that after 3 failures it did put my system back to where I first began. I'm up and running on the same version I was prior to Windows wasting 3 or 4 hours of my precious time.

I'm not asking for help, really to get around this.
View attachment 179452

Click to expand...

If you decide to upgrade again steps can be made to decrease the likelihood of failure.

And if there is a failure the log files can be troubleshooted.

it maybe worthwhile checking these

#####
please check the 'reliability monitor' to check for recent errors.
control panel > security and maintenance > maintenance > reliability monitor

#####
then check 'problem devices'
system tools > system information > components > problem devices

#####
also please open a command prompt as Administrator and write
sfc /scannow

which should repair any system errors

#####
then you can download the update and install from the download.

Microsoft Update Catalog

Click to expand...

best of luck Steve ..

glasskuter pointed on one potential cause that should be easy to test: Antivirus software. Try disabling this temporarily and see if you still get the same results. I'm pointing this one out simply because it should be rather easy to test.

Ok, I just created that one!

hsehestedt said:

glasskuter pointed on one potential cause that should be easy to test: Antivirus software. Try disabling this temporarily and see if you still get the same results. I'm pointing this one out simply because it should be rather easy to test.

Click to expand...

I have to ask the question of whether or not your referring to native anti-virus software or 3rd party anti-virus software. Because Windows 11 comes with all the native anti-malware, anti-virus, and whatever else anti they install that seems to be running constantly on the system. I haven't really used or installed any 3rd party anti-virus software for awhile now. I wouldn't think I need to disable Microsoft's native suite of anti-softwares but what the hell do I know?