Windows 11 26H2 Build 26300.9539 — File Explorer Reverted to Legacy UI

Problem Summary

After updating to Windows 11 26H2 build 26300.9539, File Explorer no longer displays the expected modern Windows 11 interface, including the tabbed File Explorer interface.

Before the update, File Explorer was using the expected Windows 11 UI. After the update, Explorer appears to have reverted to an older/legacy-style interface, and the option to use Explorer tabs is no longer available.

The issue persists across user accounts.

System Information

WindowsProductName : Windows 10 Pro
WindowsVersion     : 2009
DisplayVersion     : 26H2
CurrentBuild       : 26300
CurrentBuildNumber : 26300
EditionID          : Professional
InstallationType   : Client

DISM reports:

Image Version: 10.0.26300.9539

The Windows 10 Pro product-name string appears to be an Insider-build identification detail; the installed OS build is 26300.9539.

Explorer Information

The active Explorer process is the standard Microsoft Explorer executable:

Path           : C:\Windows\Explorer.EXE
Company        : Microsoft Corporation
Description    : Windows Explorer
ProductVersion : 10.0.26100.8117
FileVersion    : 10.0.26100.8117

ExplorerFrame.dll:

C:\Windows\System32\ExplorerFrame.dll
Size: 3268608 bytes
LastWriteTime: 9/11/2026 9:55:52 AM

Explorer.exe:

C:\Windows\Explorer.exe
Size: 3479448 bytes
LastWriteTime: 9/11/2026 9:55:51 AM

Explorer is launched normally:

Winlogon Shell:
explorer.exe

There is no evidence that a third-party Explorer executable is being used.

Windows Shell Packages

The relevant Windows shell packages are installed and report status Ok.

ShellExperienceHost

Microsoft.Windows.ShellExperienceHost
Version: 10.0.26100.8115
Status:  Ok

StartMenuExperienceHost

Microsoft.Windows.StartMenuExperienceHost
Version: 10.0.26100.4768
Status:  Ok

File Explorer package

MicrosoftWindows.Client.FileExp
Version: 1000.26100.10.0
Status:  Ok

InstallLocation:
C:\Windows\SystemApps\MicrosoftWindows.Client.FileExp_cw5n1h2txyewy

Photon

MicrosoftWindows.Client.Photon
Version: 1000.26100.10.0
Status:  Ok

Core

MicrosoftWindows.Client.Core
Version: 1000.26100.134.0
Status:  Ok

CBS

MicrosoftWindows.Client.CBS
Version: 1000.26100.372.0
Status:  Ok

Explorer Policy Checks

The following registry location was checked:

HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

It contains only:

NoRun          REG_DWORD 0x0
DisallowRun    REG_DWORD 0x0

There is no ClassicShell value.

The machine-level Explorer policies were also checked:

HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

Present values:

ForceActiveDesktopOn       REG_DWORD 0x0
NoActiveDesktop             REG_DWORD 0x1
NoActiveDesktopChanges      REG_DWORD 0x1
SettingsPageVisibility      REG_SZ hide:home

Nothing found here explains the Explorer UI reverting to the legacy interface.

Winlogon Shell

The system is configured to launch the normal Windows Explorer shell:

Shell:
explorer.exe

Userinit:
C:\Windows\system32\userinit.exe,

The current user's Winlogon Shell value is not configured.

Therefore, there is no indication that Explorer is being replaced through Winlogon configuration.

Feature Configuration

The following registry location was checked:

HKLM\SYSTEM\CurrentControlSet\Control\FeatureManagement\Overrides

No entries containing FileExp or Explorer were returned.

The following user Explorer settings were also checked for tab-related entries:

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced

No relevant Explorer-tab configuration was found.

The following policy location does not exist:

HKLM\SOFTWARE\Microsoft\PolicyManager\current\device\Shell

DISM Package Information

The installed OS reports:

Image Version: 10.0.26300.9539

The latest installed packages include:

Package_for_RollupFix ... 26100.9539.1.19

and numerous Windows components at the 26100.9539 servicing level.

This results in a system where the overall OS image is:

26300.9539

while several Explorer/shell components retain:

26100.x

component versions.

This alone does not establish corruption because Windows components can have independent package versions, but it is relevant given that the Explorer UI changed immediately following the 26300.9539 update.

User Profile Test

A completely new local Windows user account was created and File Explorer was tested from that account.

Result:

The same legacy/old Explorer interface was present.

Therefore, the problem is not limited to the original user's profile or HKCU configuration.

Troubleshooting Already Performed

The following have effectively been ruled out:

ClassicShell policy

Custom Winlogon Explorer shell

User-specific Explorer configuration

Machine-level Explorer policy causing classic Explorer

Missing MicrosoftWindows.Client.FileExp

Missing ShellExperienceHost

Missing StartMenuExperienceHost

Third-party Explorer executable

User-profile corruption

Simple Explorer package absence

SFC has also previously been run.

ViVeTool feature configuration was previously reset, but the problem remained.

Current Assessment

The evidence currently points toward a system/build-level change associated with Windows 11 26H2 build 26300.9539, rather than a corrupted user profile or an explicitly configured Classic Shell.

The problem appeared following the 26300.9539 update and persists for a newly created Windows user.

The relevant Explorer components are present and registered, but the expected modern Explorer interface and tabs are absent.

Microsoft's discussion concerning this build also indicates that File Explorer behavior changed with this update.

Current Working Hypothesis

The most likely possibilities are:

A deliberate File Explorer UI change in build 26300.9539.

A feature rollout/configuration change associated with the 26H2 Insider build.

An Explorer regression affecting some configurations after the 26300.9539 update.

Less likely, an incomplete/mismatched servicing state involving the 26300 OS build and 26100-based shell components.

There is currently insufficient evidence to justify manually replacing Explorer files or modifying arbitrary registry values.

Proposed Next Diagnostic

The cleanest A/B test is to uninstall the update corresponding to build 26300.9539, reboot, and check whether the modern Windows 11 Explorer interface and tabs return.

If Explorer immediately returns to the previous Windows 11 interface after rollback, that would strongly establish that the change is associated with build 26300.9539.

If the issue persists after rollback, further investigation of Explorer feature configuration and package registration would be warranted.

Important

No changes have been made to:

ProductName

EditionID

Explorer.exe

ExplorerFrame.dll

File Explorer system packages

Winlogon shell configuration

because there is currently no evidence that these are corrupted.

The goal is to identify whether this is a 26300.9539 regression/feature change before making invasive system modifications.

Windows 11 26H2 Build 26300.9539 — File Explorer Reverted to Legacy UI

Problem Summary

After updating to Windows 11 26H2 build 26300.9539, File Explorer no longer displays the expected modern Windows 11 interface, including the tabbed File Explorer interface.

Before the update, File Explorer was using the expected Windows 11 UI. After the update, Explorer appears to have reverted to an older/legacy-style interface, and the option to use Explorer tabs is no longer available.

The issue persists across user accounts.

System Information

WindowsProductName : Windows 10 Pro
WindowsVersion     : 2009
DisplayVersion     : 26H2
CurrentBuild       : 26300
CurrentBuildNumber : 26300
EditionID          : Professional
InstallationType   : Client

DISM reports:

Image Version: 10.0.26300.9539

The Windows 10 Pro product-name string appears to be an Insider-build identification detail; the installed OS build is 26300.9539.

Explorer Information

The active Explorer process is the standard Microsoft Explorer executable:

Path           : C:\Windows\Explorer.EXE
Company        : Microsoft Corporation
Description    : Windows Explorer
ProductVersion : 10.0.26100.8117
FileVersion    : 10.0.26100.8117

ExplorerFrame.dll:

C:\Windows\System32\ExplorerFrame.dll
Size: 3268608 bytes
LastWriteTime: 9/11/2026 9:55:52 AM

Explorer.exe:

C:\Windows\Explorer.exe
Size: 3479448 bytes
LastWriteTime: 9/11/2026 9:55:51 AM

Explorer is launched normally:

Winlogon Shell:
explorer.exe

There is no evidence that a third-party Explorer executable is being used.

Windows Shell Packages

The relevant Windows shell packages are installed and report status Ok.

ShellExperienceHost

Microsoft.Windows.ShellExperienceHost
Version: 10.0.26100.8115
Status:  Ok

StartMenuExperienceHost

Microsoft.Windows.StartMenuExperienceHost
Version: 10.0.26100.4768
Status:  Ok

File Explorer package

MicrosoftWindows.Client.FileExp
Version: 1000.26100.10.0
Status:  Ok

InstallLocation:
C:\Windows\SystemApps\MicrosoftWindows.Client.FileExp_cw5n1h2txyewy

Photon

MicrosoftWindows.Client.Photon
Version: 1000.26100.10.0
Status:  Ok

Core

MicrosoftWindows.Client.Core
Version: 1000.26100.134.0
Status:  Ok

CBS

MicrosoftWindows.Client.CBS
Version: 1000.26100.372.0
Status:  Ok

Explorer Policy Checks

The following registry location was checked:

HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

It contains only:

NoRun          REG_DWORD 0x0
DisallowRun    REG_DWORD 0x0

There is no ClassicShell value.

The machine-level Explorer policies were also checked:

HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

Present values:

ForceActiveDesktopOn       REG_DWORD 0x0
NoActiveDesktop             REG_DWORD 0x1
NoActiveDesktopChanges      REG_DWORD 0x1
SettingsPageVisibility      REG_SZ hide:home

Nothing found here explains the Explorer UI reverting to the legacy interface.

Winlogon Shell

The system is configured to launch the normal Windows Explorer shell:

Shell:
explorer.exe

Userinit:
C:\Windows\system32\userinit.exe,

The current user's Winlogon Shell value is not configured.

Therefore, there is no indication that Explorer is being replaced through Winlogon configuration.

Feature Configuration

The following registry location was checked:

HKLM\SYSTEM\CurrentControlSet\Control\FeatureManagement\Overrides

No entries containing FileExp or Explorer were returned.

The following user Explorer settings were also checked for tab-related entries:

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced

No relevant Explorer-tab configuration was found.

The following policy location does not exist:

HKLM\SOFTWARE\Microsoft\PolicyManager\current\device\Shell

DISM Package Information

The installed OS reports:

Image Version: 10.0.26300.9539

The latest installed packages include:

Package_for_RollupFix ... 26100.9539.1.19

and numerous Windows components at the 26100.9539 servicing level.

This results in a system where the overall OS image is:

26300.9539

while several Explorer/shell components retain:

26100.x

component versions.

This alone does not establish corruption because Windows components can have independent package versions, but it is relevant given that the Explorer UI changed immediately following the 26300.9539 update.

User Profile Test

A completely new local Windows user account was created and File Explorer was tested from that account.

Result:

The same legacy/old Explorer interface was present.

Therefore, the problem is not limited to the original user's profile or HKCU configuration.

Troubleshooting Already Performed

The following have effectively been ruled out:

ClassicShell policy

Custom Winlogon Explorer shell

User-specific Explorer configuration

Machine-level Explorer policy causing classic Explorer

Missing MicrosoftWindows.Client.FileExp

Missing ShellExperienceHost

Missing StartMenuExperienceHost

Third-party Explorer executable

User-profile corruption

Simple Explorer package absence

SFC has also previously been run.

ViVeTool feature configuration was previously reset, but the problem remained.

Current Assessment

The evidence currently points toward a system/build-level change associated with Windows 11 26H2 build 26300.9539, rather than a corrupted user profile or an explicitly configured Classic Shell.

The problem appeared following the 26300.9539 update and persists for a newly created Windows user.

The relevant Explorer components are present and registered, but the expected modern Explorer interface and tabs are absent.

Microsoft's discussion concerning this build also indicates that File Explorer behavior changed with this update.

Current Working Hypothesis

The most likely possibilities are:

A deliberate File Explorer UI change in build 26300.9539.

A feature rollout/configuration change associated with the 26H2 Insider build.

An Explorer regression affecting some configurations after the 26300.9539 update.

Less likely, an incomplete/mismatched servicing state involving the 26300 OS build and 26100-based shell components.

There is currently insufficient evidence to justify manually replacing Explorer files or modifying arbitrary registry values.

Proposed Next Diagnostic

The cleanest A/B test is to uninstall the update corresponding to build 26300.9539, reboot, and check whether the modern Windows 11 Explorer interface and tabs return.

If Explorer immediately returns to the previous Windows 11 interface after rollback, that would strongly establish that the change is associated with build 26300.9539.

If the issue persists after rollback, further investigation of Explorer feature configuration and package registration would be warranted.

Important

No changes have been made to:

ProductName

EditionID

Explorer.exe

ExplorerFrame.dll

File Explorer system packages

Winlogon shell configuration

because there is currently no evidence that these are corrupted.

The goal is to identify whether this is a 26300.9539 regression/feature change before making invasive system modifications.

Hi Taha

There have been changes to File

Explorer with your build, so that could

be the answer.

And if you Uninstall the latest update it

might only change back again with the next

update.

Hi,

Please remember to file the issue

in the Feedback Hub using WIN+F.