[Fix] .NET Framework 3.5 Installation Error 0x800F0922

When you install the latest cumulative update or the .NET Framework 3.5 using OptionalFeatures.exe, the installation may rollback with the error code 0x800F0922.

When the latest cumulative update fails, the CBS log may contain the following entry:

Error                 CSI    000001f9 (F) Done with generic command 2; CreateProcess returned 0, CPAW returned S_OK
    Process exit code 3222072836 resulted in success? false
    Process output: [l:71 [71'SMConfigInstaller[Error]: Installation failed with error: 0xc00cee04

(or)

Error                 CSI    00000079 (F) STATUS_SXS_COMPONENT_STORE_CORRUPT #3383790# from Windows::Rtl::SystemImplementation::CSystemIsolationLayer::TransferFileEx(flags = (ReplaceIfExists|OpenForBackupIntent|SharingViolationIsOk|TransactionalConflictIsOk|CannotDeleteIsOk|DeletePendingIsOk|OpenForSecurityAccess|ManageVolumePrivAlreadyAcquired), op = 'Move', odir = (null), oname = [l:71]'\??\C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\machine.config', sfile = (null), ndir = (null), nname = [l:86]'\SystemRoot\WinSxS\Temp\Pen[gle=0xd015001a]
2025-10-30 22:07:02, Error                 CSI    dingDeletes\9e8b10508d49dc0136010000ec1a4c2f.machine.config', disp = Unmapped disposition: 0)
[gle=0xd015001a]

This can happen if the .NET Framework configuration files are corrupted. Resetting them should fix the error.

Resolution

Open an elevated Command Prompt window and run these commands:

cd /d C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\CONFIG
del web.config
del machine.config
del web_mediumtrust.config
copy web.config.default web.config
copy machine.config.default machine.config
copy web_mediumtrust.config.default  web_mediumtrust.config

cd /d C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG
del web.config
del machine.config
del web_mediumtrust.config
copy web.config.default web.config
copy machine.config.default machine.config
copy web_mediumtrust.config.default  web_mediumtrust.config

cd /d C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config
del web.config
del machine.config
del web_mediumtrust.config
copy web.config.default web.config
copy machine.config.default machine.config
copy web_mediumtrust.config.default  web_mediumtrust.config

cd /d C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config
del web.config
del machine.config
del web_mediumtrust.config
copy web.config.default web.config
copy machine.config.default machine.config
copy web_mediumtrust.config.default  web_mediumtrust.config

See if that fixes the .NET Framework 3.5 or the LCU installation error.

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