Complete list of Windows Update error codes

Every Windows Update error code is a hexadecimal value, and its first four digits tell you which part of Windows failed: 0x8024 is the Windows Update Agent, 0x8007 is a standard Win32 error, 0x800F is the servicing stack, and 0xC1900 is Windows Setup.

This reference lists the codes Microsoft documents for Windows 11 and Windows 10, grouped by component, with the official fix for the errors people hit most often.

Where to find the Windows Update error code

Windows shows the code next to the failed update in Settings. The update history page keeps it after you close the window, so you can copy it later.

1. Press Win + R to open Run.
2. Type ms-settings:windowsupdate-history and press Enter to open View update history.
3. Find the update marked as failed and note the code shown with it, for example 0x800f081f.
4. On Windows 10, the same page is under Settings > Update & Security > Windows Update > View update history.
5. Match the first four digits of the code to the prefix table in the next section, then look up the full code in the tables below.

If Settings shows no code, generate the readable WindowsUpdate.log with PowerShell and search it for the word FAILED. The log section further down shows the command.

Upgrade failures from Setup or the Windows Update Assistant can return only a result code such as 0xC1900101. Event Viewer can still hold the extended code in its Windows Error Reporting entries.

Decoding Windows Update error codes

Microsoft groups update errors by the component that raised them. The leading digits identify that component, and the trailing digits identify the exact failure.

For codes that start with 0x8007, the last four digits are a plain Win32 error. 0x80070070 ends in 0070, which is 112 in decimal: ERROR_DISK_FULL.

Code starts with	Component	Message prefix	How to read it
0x8024	Windows Update Agent (scan, download, install engine)	WU_E_	Look up the full code in the agent tables below
0x8007	Win32 system error passed up by Windows	ERROR_	Take the last four digits and match them to the Win32 System Error Codes list
0x800F	Component-Based Servicing (CBS), the servicing stack	CBS_E_ or PSFX_E_	Usually component store corruption; repair with DISM and SFC
0xC1900	Windows Setup during a feature update or upgrade	MOSETUP_E_	0xC1900101 means a rollback, most often caused by a driver
0x8020	Background Intelligent Transfer Service (BITS)	BG_E_	Download validation failed, often a filtering firewall
0x80D0	Delivery Optimization download path	DO_E_	Download timed out or a proxy does not allow HTTP RANGE requests
0x8007 2Exx / 2Fxx	WinINet network layer	WININET_E_	Connection, timeout or TLS problem between the PC and the update servers
0x0024	Windows Update success codes	WU_S_	Not an error; the operation finished, sometimes with a restart pending

An upgrade result code beginning with 8 is a Win32 error, while one beginning with C is an NTSTATUS value. Both are decoded from their last four digits.

Common Windows Update errors

These are the codes Microsoft documents most often for home and business PCs, with the fix Microsoft gives for each.

Error code	Meaning	Official fix
0x80070002	ERROR_FILE_NOT_FOUND: a file the update needs is missing	Restart, run the Windows Update troubleshooter and free up drive space
0x80070003	ERROR_PATH_NOT_FOUND: the servicing stack cannot reach a path	Restart and run the troubleshooter; admins search CBS.log for the error
0x80070005	E_ACCESSDENIED: file or registry permissions were changed	Sign in with an administrator account and retry
0x8007000D	ERROR_INVALID_DATA: downloaded data is corrupt	Run the troubleshooter and clear the update cache, then download again
0x80070020	ERROR_SHARING_VIOLATION: a file is locked by another program	Restart, perform a clean boot and retry the installation
0x80070057	ERROR_INVALID_PARAMETER	Run sfc /scannow and the troubleshooter
0x80070422	ERROR_SERVICE_DISABLED: Windows Update service is not running	Set the Windows Update service to Automatic, start it and restart
0x80070490	ERROR_NOT_FOUND during a driver install in the update	Admins add the missing driver Arch value under the DriverOperations registry key
0x800705B4	Operation timed out	Check the connection, run the troubleshooter and restart
0x8007371B	ERROR_SXS_TRANSACTION_CLOSURE_INCOMPLETE: component store corruption	Run DISM RestoreHealth, then sfc /scannow, then restart
0x80073712	ERROR_SXS_COMPONENT_STORE_CORRUPT	Run DISM RestoreHealth and sfc /scannow
0x800F081F	CBS_E_SOURCE_MISSING: repair source not found	Run DISM RestoreHealth and sfc /scannow
0x800F0831	CBS_E_STORE_CORRUPTION: CBS store is corrupted	Run DISM RestoreHealth and sfc /scannow
0x800F0922	CBS_E_INSTALLERS_FAILED	Free up drive space, disconnect any VPN and perform a clean boot
0x80240034	WU_E_DOWNLOAD_FAILED: the update failed to download	Check the Windows Update service and run the troubleshooter
0x80246007	WU_E_DM_NOTDOWNLOADED: the update has not been downloaded	Reset the update services, run the troubleshooter and restart
0x80248014	WU_E_DS_UNKNOWNSERVICE	Run the troubleshooter and start the Windows Update service
0x80072EE2	WININET_E_TIMEOUT: cannot reach the update servers	Check that the PC can reach the Windows Update endpoints
0x80072EFE	WININET_E_CONNECTION_ABORTED: the connection closed abnormally	Check proxy and network settings, then retry
0x80072F8F	WININET_E_DECODING_FAILED: TLS 1.2 is not set up correctly	Install and configure TLS 1.2 on the client
0xC1900101	Generic rollback during a feature update	Update or reinstall network and graphics drivers, then clean boot

Where Microsoft lists DISM and SFC as the fix, the repair commands are in the DISM section below. Keep your Windows Update settings at their defaults while you troubleshoot so a policy does not block the retry.

Windows Update Agent error codes by component

Every 0x8024 code falls in a range owned by one part of the Windows Update Agent. The range tells you whether the problem was the scan, the download or the install.

Code range	Component	Typical meaning
0x80240001 to 0x80240FFF	General Windows Update errors	Service, policy, network and metadata failures
0x80241001 to 0x80241FFF	Windows Installer minor errors	Search may have missed updates because of Windows Installer
0x80242000 to 0x80242FFF	Update Handler	The installer for the update failed or needs a restart
0x80243001 to 0x80243FFF	Windows Update UI	Install results could not be read or shown
0x80244000 to 0x80244FFF	Protocol Talker	Client-server sync and HTTP errors
0x80245001 to 0x80245FFF	Redirector	The Wuredir.cab file could not be loaded or parsed
0x80246001 to 0x80246FFF	Download Manager	BITS transfer and file hash failures
0x80247001 to 0x80247FFF	Offline scan	The scan package was invalid or needs a newer agent
0x80248000 to 0x80248FFF	Data Store	The local update database is locked, damaged or missing data
0x80249001 to 0x80249005	Inventory	Inventory rule parsing or upload failed
0x8024A000 to 0x8024AFFF	Automatic Updates	Automatic Updates is paused or cannot service requests
0x8024C001 to 0x8024CFFF	Driver Util	A driver update was skipped or is missing metadata
0x8024D001 to 0x8024DFFF	Windows Update Agent setup	The agent could not update itself
0x8024E001 to 0x8024EFFF	Expression evaluator	Applicability rules in the update could not be evaluated
0x8024F001 to 0x8024FFFF	Reporter	The event cache or reporting to the server failed

Windows Update error codes 0x80240001 to 0x80240FFF

Error code	Message	Description
0x80240001	WU_E_NO_SERVICE	Windows Update Agent could not provide the service
0x80240002	WU_E_MAX_CAPACITY_REACHED	The maximum capacity of the service was exceeded
0x80240003	WU_E_UNKNOWN_ID	An ID cannot be found
0x80240004	WU_E_NOT_INITIALIZED	The object could not be initialized
0x80240005	WU_E_RANGEOVERLAP	A requested byte range overlaps an earlier range
0x80240006	WU_E_TOOMANYRANGES	Too many byte ranges were requested
0x80240007	WU_E_INVALIDINDEX	The index to a collection was invalid
0x80240008	WU_E_ITEMNOTFOUND	The key for the queried item could not be found
0x80240009	WU_E_OPERATIONINPROGRESS	Another conflicting operation, such as an install, was running
0x8024000A	WU_E_COULDNOTCANCEL	Cancelling the operation was not allowed
0x8024000B	WU_E_CALL_CANCELLED	The operation was cancelled by the user or service
0x8024000C	WU_E_NOOP	No operation was required
0x8024000D	WU_E_XML_MISSINGDATA	Required information is missing from the update's XML data
0x8024000E	WU_E_XML_INVALID	The update's XML data contains invalid information
0x8024000F	WU_E_CYCLE_DETECTED	Circular update relationships were found in the metadata
0x80240010	WU_E_TOO_DEEP_RELATION	Update relationships were too deep to evaluate
0x80240011	WU_E_INVALID_RELATIONSHIP	An invalid update relationship was detected
0x80240012	WU_E_REG_VALUE_INVALID	An invalid registry value was read
0x80240013	WU_E_DUPLICATE_ITEM	A duplicate item was added to a list
0x80240016	WU_E_INSTALL_NOT_ALLOWED	Another install was running or a mandatory restart was pending
0x80240017	WU_E_NOT_APPLICABLE	There are no applicable updates
0x80240018	WU_E_NO_USERTOKEN	A required user token is missing
0x80240019	WU_E_EXCLUSIVE_INSTALL_CONFLICT	An exclusive update cannot install alongside other updates
0x8024001A	WU_E_POLICY_NOT_SET	A policy value was not set
0x8024001B	WU_E_SELFUPDATE_IN_PROGRESS	The Windows Update Agent is updating itself
0x8024001D	WU_E_INVALID_UPDATE	An update contains invalid metadata
0x8024001E	WU_E_SERVICE_STOP	The service or system was shutting down
0x8024001F	WU_E_NO_CONNECTION	The network connection was unavailable
0x80240020	WU_E_NO_INTERACTIVE_USER	No interactive user is signed in
0x80240021	WU_E_TIME_OUT	The operation timed out
0x80240022	WU_E_ALL_UPDATES_FAILED	The operation failed for all updates
0x80240023	WU_E_EULAS_DECLINED	License terms for all updates were declined
0x80240024	WU_E_NO_UPDATE	There are no updates
0x80240025	WU_E_USER_ACCESS_DISABLED	Group Policy prevented access to Windows Update
0x80240026	WU_E_INVALID_UPDATE_TYPE	The type of update is invalid
0x80240027	WU_E_URL_TOO_LONG	The URL exceeded the maximum length
0x80240028	WU_E_UNINSTALL_NOT_ALLOWED	The uninstall request did not come from a WSUS server
0x80240029	WU_E_INVALID_PRODUCT_LICENSE	Search may have missed updates because of an unlicensed application
0x8024002A	WU_E_MISSING_HANDLER	A component needed to detect updates was missing
0x8024002B	WU_E_LEGACYSERVER	The operation needs a newer server version
0x8024002C	WU_E_BIN_SOURCE_ABSENT	A delta update needed its source to install
0x8024002D	WU_E_SOURCE_ABSENT	A full-file update needed its source to install
0x8024002E	WU_E_WU_DISABLED	Access to an unmanaged server is not allowed
0x8024002F	WU_E_CALL_CANCELLED_BY_POLICY	The DisableWindowsUpdateAccess policy was set
0x80240030	WU_E_INVALID_PROXY_SERVER	The proxy list format was invalid
0x80240031	WU_E_INVALID_FILE	The file is in the wrong format
0x80240032	WU_E_INVALID_CRITERIA	The search criteria string was invalid
0x80240033	WU_E_EULA_UNAVAILABLE	License terms could not be downloaded
0x80240034	WU_E_DOWNLOAD_FAILED	The update failed to download
0x80240035	WU_E_UPDATE_NOT_PROCESSED	The update was not processed
0x80240036	WU_E_INVALID_OPERATION	The object's current state did not allow the operation
0x80240037	WU_E_NOT_SUPPORTED	The operation is not supported
0x80240038	WU_E_WINHTTP_INVALID_FILE	The downloaded file has an unexpected content type
0x80240039	WU_E_TOO_MANY_RESYNC	The server asked the agent to resync too many times
0x80240040	WU_E_NO_SERVER_CORE_SUPPORT	The API method does not run on Server Core
0x80240041	WU_E_SYSPREP_IN_PROGRESS	The service is unavailable while Sysprep runs
0x80240042	WU_E_UNKNOWN_SERVICE	The update service is no longer registered with Automatic Updates
0x80240043	WU_E_NO_UI_SUPPORT	There is no support for the Windows Update UI
0x80240FFF	WU_E_UNEXPECTED	A failure not covered by another error code

Windows Update download and install error codes

Download Manager codes (0x80246) and Update Handler codes (0x80242) cover the two stages where most failed updates stop.

Error code	Message	Description
0x80246001	WU_E_DM_URLNOTAVAILABLE	The requested file has no URL
0x80246002	WU_E_DM_INCORRECTFILEHASH	The file digest was not recognized
0x80246003	WU_E_DM_UNKNOWNALGORITHM	The file metadata asked for an unknown hash algorithm
0x80246004	WU_E_DM_NEEDDOWNLOADREQUEST	A download request is required from the handler
0x80246005	WU_E_DM_NONETWORK	The network connection was unavailable
0x80246006	WU_E_DM_WRONGBITSVERSION	The BITS version is incompatible
0x80246007	WU_E_DM_NOTDOWNLOADED	The update has not been downloaded
0x80246008	WU_E_DM_FAILTOCONNECTTOBITS	The download manager could not connect to BITS
0x80246009	WU_E_DM_BITSTRANSFERERROR	An unspecified BITS transfer error occurred
0x8024600A	WU_E_DM_DOWNLOADLOCATIONCHANGED	The download source moved; the download must restart
0x8024600B	WU_E_DM_CONTENTCHANGED	The update content changed in a new revision
0x80246017	WU_E_DM_UNAUTHORIZED_LOCAL_USER	The local user was not authorized to download the content
0x80242006	WU_E_UH_INVALIDMETADATA	The update contains invalid metadata
0x80242007	WU_E_UH_INSTALLERHUNG	The installer exceeded the time limit
0x80242008	WU_E_UH_OPERATIONCANCELLED	The update handler operation was cancelled
0x8024200A	WU_E_UH_CANREQUIREINPUT	The update needs user input to install
0x8024200B	WU_E_UH_INSTALLERFAILURE	The installer failed to install or uninstall one or more updates
0x8024200D	WU_E_UH_NEEDANOTHERDOWNLOAD	The update must be downloaded again
0x80242012	WU_E_UH_UNEXPECTEDCBSRESPONSE	The handler received an unexpected response from CBS
0x80242014	WU_E_UH_POSTREBOOTSTILLPENDING	The post-restart operation is still in progress; restart the PC
0x80242015	WU_E_UH_POSTREBOOTRESULTUNKNOWN	The result of the post-restart operation is unknown
0x80242017	WU_E_UH_NEW_SERVICING_STACK_REQUIRED	The servicing stack must be updated first

Windows Update HTTP and connection error codes

Protocol Talker codes mirror HTTP status codes from the update server or a proxy, so a 0x8024401x or 0x8024402x code points at the network path, not at Windows itself.

Error code	Message	HTTP meaning
0x80244016	WU_E_PT_HTTP_STATUS_BAD_REQUEST	400: invalid request syntax
0x80244017	WU_E_PT_HTTP_STATUS_DENIED	401: user authentication required
0x80244018	WU_E_PT_HTTP_STATUS_FORBIDDEN	403: the server refused the request
0x80244019	WU_E_PT_HTTP_STATUS_NOT_FOUND	404: the requested URI was not found
0x8024401B	WU_E_PT_HTTP_STATUS_PROXY_AUTH_REQ	407: proxy authentication required
0x8024401C	WU_E_PT_HTTP_STATUS_REQUEST_TIMEOUT	408: the server timed out waiting for the request
0x8024401F	WU_E_PT_HTTP_STATUS_SERVER_ERROR	500: internal server error
0x80244021	WU_E_PT_HTTP_STATUS_BAD_GATEWAY	502: bad response from an upstream server
0x80244022	WU_E_PT_HTTP_STATUS_SERVICE_UNAVAIL	503: the service is temporarily overloaded
0x80244023	WU_E_PT_HTTP_STATUS_GATEWAY_TIMEOUT	Gateway timeout
0x8024402C	WU_E_PT_WINHTTP_NAME_NOT_RESOLVED	The proxy or server name could not be resolved
0x8024402F	WU_E_PT_ECP_SUCCEEDED_WITH_ERRORS	External cab processing finished with errors
0x80244007	WU_E_PT_SOAPCLIENT_SOAPFAULT	Windows cannot renew the cookies for Windows Update
0x80072EFD	TIME_OUT_ERRORS	The connection timed out; check firewall rules and proxies
0x80D02002	TIME_OUT_ERRORS	The download timed out; check firewall rules and proxies
0x80D05001	DO_E_HTTP_BLOCKSIZE_MISMATCH	The proxy does not allow HTTP RANGE requests
0x80200053	BG_E_VALIDATION_FAILED	A firewall that filters downloads returned an incorrect response

Windows Update corruption error codes 0x800F and 0x8007

Microsoft lists these codes as signs of a damaged component store or system file. All of them share one fix: DISM followed by SFC.

Error code	Message	Description
0x800F0906	CBS_E_DOWNLOAD_FAILURE	Content download failed for a Feature on Demand or a corruption repair
0x800F0982	PSFX_E_MATCHING_COMPONENT_NOT_FOUND	No matching component could be found for hydration
0x800F0984	PSFX_E_MATCHING_BINARY_MISSING	The component folder exists but the binary is missing
0x800F0986	PSFX_E_APPLY_FORWARD_DELTA_FAILED	Applying a forward delta failed
0x800F0821	CBS_E_ABORT	A servicing operation exceeded the CBS timeout
0x800F0825	CBS_E_CANNOT_UNINSTALL	A package cannot be uninstalled because of a partly installed component
0x800F0920	CBS_E_HANG_DETECTED	Servicing stopped responding after a 0x800f0821 timeout
0x80070570	ERROR_FILE_CORRUPT	A file or directory is corrupted and unreadable
0x80073701	ERROR_SXS_ASSEMBLY_MISSING	A referenced assembly could not be found
0x800736CC	ERROR_SXS_FILE_HASH_MISMATCH	A component file does not match its manifest
0x8007370D	ERROR_SXS_IDENTITY_PARSE_ERROR	An identity string is malformed
0x800705B9	ERROR_XML_PARSE_ERROR	The requested XML data could not be parsed
0x800B0100	TRUST_E_NOSIGNATURE	No signature was present in the file
0x800B0101	CERT_E_EXPIRED	A required certificate is outside its validity period for the system clock
0x80092003	CRYPT_E_FILE_ERROR	Windows Update could not read or write a file

CERT_E_EXPIRED is checked against the system clock, so a wrong date can trigger it on a healthy PC.

Windows upgrade error codes 0xC1900

Feature updates and in-place upgrades run Windows Setup, which returns a result code and, when it can, an extend code that names the phase where it failed.

Result code	Message	Meaning
0xC1900101	Rollback	Setup failed and rolled back; usually a driver compatibility issue
0xC1900200	MOSETUP_E_COMPAT_SYSREQ_BLOCK	The PC is not eligible for the target Windows version
0xC1900204	MOSETUP_E_COMPAT_MIGCHOICE_BLOCK	The chosen migration path is not available, for example Enterprise to Home
0xC1900208	MOSETUP_E_COMPAT_INSTALLREQ_BLOCK	An actionable compatibility issue, such as an incompatible app
0xC190020E	MOSETUP_E_INSTALLDISKSPACE_BLOCK	Not enough free space to install
0xC1900210	MOSETUP_E_COMPAT_SCANONLY	Setup found no compatibility issue

In an extend code such as 0x4000D, the first digit is the phase (4 is the OOBE boot) and the last two digits are the operation (0D is data migration).

Fix Windows Update corruption errors with DISM and SFC

Microsoft's fix for 0x800F081F, 0x800F0831, 0x80073712, 0x8007371B and 0x80070570 is the same two commands. Open Command Prompt with Run as administrator first.

DISM.exe /Online /Cleanup-image /Restorehealth

Checks the Windows component store against Microsoft Update and replaces damaged files. Run sfc /scannow straight after it to repair protected system files, then restart and check for updates again.

You should see: DISM reports "The restore operation completed successfully". If it fails, the details are in %windir%\Logs\CBS\CBS.log.

Reset Windows Update components to clear download errors

Codes such as 0x8007000D, 0x80242006 and 0x80246007 often come from a damaged download cache. Renaming the cache folders makes Windows download the update again.

1. Open Command Prompt as administrator.
2. Type net stop wuauserv and press Enter to stop the Windows Update service.
3. Type net stop bits and press Enter to stop BITS.
4. Type ren %systemroot%\SoftwareDistribution SoftwareDistribution.old and press Enter.
5. Type ren %systemroot%\system32\catroot2 catroot2.old and press Enter.
6. Type net start bits and then net start wuauserv, pressing Enter after each.
7. Restart the PC and run Check for updates again.

If the check still returns nothing, you can force a Windows 11 update from the Microsoft Update Catalog or Command Prompt.

Read the Windows Update log with Get-WindowsUpdateLog

Windows writes update traces as .etl files that you cannot read directly. This PowerShell cmdlet merges them into one readable text file.

Get-WindowsUpdateLog

Converts the trace files in C:\Windows\Logs\WindowsUpdate into WindowsUpdate.log on your desktop. Add -LogPath to save it somewhere else. The file is a snapshot, so run the cmdlet again after each new failure.

You should see: PowerShell prints "WindowsUpdate.log written to" followed by the desktop path. Open the file and search for FAILED or the error code.

Installation errors that start with 0x800F are written to %systemroot%\Logs\CBS\CBS.log instead, which is the servicing stack's own log.

Confirm a Windows update installed with Get-HotFix

1. Open PowerShell.
2. Type Get-HotFix KB5000000, replacing the number with the KB number of the update that failed, and press Enter.
3. Read the InstalledOn column. A date there means the update is now installed.
4. If PowerShell returns an error that the hotfix cannot be found, the update is still missing; open View update history again for the new code.

Windows Update error troubleshooting by symptom

Update stuck at 0% or 100%

A stalled download, a lost connection or a full drive stops the update between stages.

1. Restart the PC and check the internet connection.
2. Make sure the system drive has at least 20 GB free on 64-bit Windows.
3. Run the Windows Update troubleshooter from Settings > System > Troubleshoot > Other troubleshooters.
4. Select Check for updates again.

Error 0x80070422: Windows Update service disabled

The Windows Update service is stopped or its startup type was changed.

1. Press Win + R, type services.msc and press Enter.
2. Double-click Windows Update.
3. Set Startup type to Automatic and select Start.
4. Select OK, restart the PC and check for updates.

Error 0x80072EE2, 0x80072EFE or 0x8024401B: cannot connect

A proxy, firewall or network filter blocks the Windows Update endpoints.

1. Open a site in your browser to confirm the connection works.
2. Check the date and time under Settings > Time & language > Date & time and turn on automatic time.
3. If a proxy is set only in user settings, open Command Prompt as administrator and run netsh winhttp import proxy source=ie.
4. Disconnect any VPN and retry the update.

Error 0x80070005: access denied

The account or the servicing stack lacks permission to a file or registry key.

1. Sign out and sign in with an administrator account.
2. Run Check for updates again.
3. If the error repeats, run DISM and SFC as shown above, then restart.

Error 0x80070020 or 0x80240022: file locked or all updates failed

Another program, often security or backup software, holds a file the update needs.

1. Perform a clean boot so only Microsoft services start.
2. Retry the installation.
3. Restart normally once the update completes.

Error 0xC1900101 during a feature update

A driver, usually network or graphics, is not compatible with the new version.

1. Disconnect external drives, docks and other hardware you do not need.
2. Open Device Manager and update the network and graphics drivers from the hardware maker.
3. Perform a clean boot and run the feature update again.

Windows Update error codes FAQ

Where is the full list of Windows Update error codes?

Microsoft publishes it on Microsoft Learn as Windows Update error codes by component. It groups every 0x8024 code by the agent component that raised it, and a separate common errors page adds the fix for the codes people hit most.

What does 0x8024 at the start of an error code mean?

It means the Windows Update Agent itself reported the failure. The next digit names the component: 0x80244 is server communication, 0x80246 is the download manager, 0x80242 is the update installer and 0x80248 is the local update database.

What does a 0x8007 Windows Update error mean?

A 0x8007 code wraps a standard Win32 system error. Take the last four digits and look them up in the Win32 System Error Codes list: 0x80070002 is file not found, 0x80070005 is access denied and 0x80070070 is a full disk.

How do I fix error 0x800f081f?

Error 0x800f081f means the servicing stack could not find a repair source because the component store is damaged. Run DISM with /Online /Cleanup-Image /RestoreHealth, then sfc /scannow from an administrator Command Prompt, restart the PC and install the update again.

What is error 0xC1900101?

0xC1900101 is a generic rollback code from Windows Setup during a feature update. Microsoft says the cause is usually a driver compatibility problem, so update network and graphics drivers, disconnect extra hardware and retry from a clean boot.

Where is the Windows Update log file?

Windows stores update traces in C:\Windows\Logs\WindowsUpdate as .etl files. Run Get-WindowsUpdateLog in PowerShell to turn them into a readable WindowsUpdate.log on your desktop. Installation errors are also written to CBS.log in C:\Windows\Logs\CBS.

Is a 0x00240005 code an error?

No. Codes that start with 0x0024 are Windows Update success codes. 0x00240005, WU_S_REBOOT_REQUIRED, means the update installed and Windows needs a restart to finish, so restart the PC rather than troubleshoot.

Does the Windows Update troubleshooter fix error codes?

It fixes many of them. Microsoft lists running the troubleshooter as a first step for codes such as 0x8007000d, 0x80240034, 0x80248014 and 0x80070002. On Windows 11 it is under Settings, System, Troubleshoot, Other troubleshooters.