File Explorer reverts to legacy Windows 10 ribbon after KB5120998 (build 26200.9278) — 766 corrupt OOBE payloads in component store; RestoreHealth fails with 0x800f0915

Question

File Explorer reverts to legacy Windows 10 ribbon after KB5120998 (build 26200.9278) — 766 corrupt OOBE payloads in component store; RestoreHealth fails with 0x800f0915

Ryfried 0

Environment: Windows 11 25H2, x64. Build 26200.9278 (KB5120998) was installed on Sep 8, 2026.

Symptom

Before the issue is fixed After the update, File Explorer opened with the legacy Windows 10 ribbon UI — no tabs, no modern command bar, no address/search band. It persisted after restarting explorer.exe, after a reboot, and in Safe Mode.

Diagnostics (elevated)

SFC /scannow: no integrity violations (live files match the component store).
DISM /ScanHealth: "The component store is repairable" — 766 CSI payload corruption entries, all in one component: amd64_userexperience-oobe_31bf3856ad364e35_10.0.26100.1591_none_54983d2d7a4908c4 (OOBE\resources.pri, WebExperienceHost.dll, WebHost.winmd, webapps\guidedsetup...\area-content.local.json). Manifest and metadata corruption: 0.
DISM /RestoreHealth: fails with 0x800f0915 "The repair content could not be found anywhere" (download stalls, then fails). The same failure is recorded in C:\Windows\Logs\DISM\dism.log on July 23, 2026, so the store has been unrepairable via Windows Update for weeks.
chkdsk /scan: clean, 0 bad sectors.
During KB5120998's online servicing phase (Sep 8 ~22:00), AppX registration failed repeatedly with 0x80070570 (ERROR_FILE_CORRUPT) for MicrosoftWindows.Client.OOBE, MicrosoftWindows.Client.CBS (344.0 -> 360.0), Microsoft.Windows.StartMenuExperienceHost, Microsoft.AAD.BrokerPlugin, plus "Failed to notify RDS of recovery trigger".

Workaround that fixed the shell

DISM /Online /Remove-Package /PackageName:Package_for_RollupFix~31bf3856ad364e35~amd64~~26100.9278.1.35 (exit 3010) followed by a reboot. The modern File Explorer immediately returned; the machine is now on build 26200.9168.

After the issue is fixed, the new WinUI is back. Questions

How can the corrupt OOBE payloads in the component store be repaired when Windows Update cannot supply repair content (0x800f0915)? Will an in-place repair upgrade from a 25H2 ISO fix it?
Is the next cumulative update at risk of failing the same way while this corruption remains?
Is this File Explorer legacy-ribbon fallback a known issue on 25H2 after LCU installation, and is there an official fix?

Refer to the After Action Report file for more detailed report. FileExplorer-Fallback-AAR.pdf

0 comments

1 answer

Your answer

Answer 1

Hi Ryfried,

Thank you for sharing the detailed report. Uninstalling KB5120998 restored the modern File Explorer, but the remaining OOBE payload corruption indicates that the underlying component-store issue is still present.

Could you confirm whether you have tried DISM /RestoreHealth using a matching Windows 11 25H2 ISO? If so, please share the ISO build and the result. Also, has Windows offered or installed another cumulative update since the rollback?

If a matching ISO source also fails with 0x800f0915, I recommend backing up important files and performing an in-place repair upgrade. Run setup.exe from within Windows and ensure Keep personal files and apps is selected. I would avoid reinstalling KB5120998 until the component store has been repaired.

You may also check the device manufacturer’s support page for an approved Intel RST VMD driver update, although the available evidence does not confirm that the current driver caused the corruption.

Please share the ISO repair result so I can advise further.

If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.