How to fix Windows update error 0x80072f76?

Error 0x80072F76 means a reply from Microsoft's servers came back without a header Windows expected, so the download stops. Most people see it in the Media Creation Tool or an upgrade assistant, less often in Windows Update. Start with a fresh, unblocked copy of the tool run as administrator (Fix 1), then check for a proxy or VPN (Fix 2).

Facts checked on 15 October 2026. Steps written for Windows 11 (25H2 and 26H2) and Windows 10 22H2.

What error 0x80072F76 means

The code has two parts. 0x8007 marks a Windows system error, and 2F76 is the number 12150 in hexadecimal. In Microsoft's list of WinINet errors, 12150 is ERROR_HTTP_HEADER_NOT_FOUND: "The requested header could not be located." WinINet is the Windows library that setup tools use to download files over the internet.

In plain words: the tool asked a Microsoft server for a file, an answer came back, but a part of that answer the tool needs was missing. The internet works, yet this one download cannot go on. That is why the error often appears in the first minute, before any progress is shown.

Why the download fails with 0x80072F76

A missing header means the answer from the server was cut short or changed on its way to your PC. That points at the tool itself or at something in the middle of the connection. A damaged Windows Update cache is only a cause when the error shows in Windows Update.

0x80072F76 on a work or school PC: The sync could not be initiated

Search results show many reports of The sync could not be initiated (0x80072f76) on PCs managed by a company or school. It appears when you select Sync under Settings > Accounts > Access work or school. The code is the same WinINet error, so the PC got an incomplete answer from its management service.

• Check whether a proxy is set with Fix 2, but do not remove a proxy your company requires.
• Note the time, the code and whether the error appears on every network or only one.
• Send these details to your IT team. We could not confirm one cause of this message from a Microsoft source we read today, and the fix is usually on the management side.

How to fix error 0x80072F76 in Windows

Fixes 1 to 4 are for the Media Creation Tool and the upgrade assistants, where most readers meet this error. Fix 5 finds a program in the way. Fixes 6 to 8 are for the case when Windows Update itself shows 0x80072F76.

Fix 1. Download a fresh copy of the tool, unblock it and run it as administrator

5 minutesNo riskThe Media Creation Tool, the Update Assistant or the Installation Assistant shows 0x80072F76.

Microsoft support asked readers with this code whether the setup tool was damaged or came from another site. An old copy can ask for files in a way the servers no longer answer, and Windows can block a downloaded file until you allow it.

1. Delete every older copy of the tool from Downloads and the desktop, such as MediaCreationTool.exe or an older assistant file.
2. Download the tool again from Microsoft's software download page for Windows 11, or for Windows 10 if you still need it. Use no other website.
3. Right-click the new file and select Properties. Stay on the General tab.
4. If you see an Unblock checkbox in the Security line at the bottom, tick it, then select Apply and OK. No checkbox means the file is not blocked.
5. Right-click the file and select Run as administrator, then Yes in User Account Control.
6. Accept the licence terms and choose what you want to do.

Fix 2. Remove the proxy, disconnect the VPN and stop HTTPS scanning

5 to 10 minutesLow riskFix 1 did not help, you use a VPN or a filter, or Windows Update shows the code.

A proxy, a VPN or a security app that scans HTTPS opens the download and passes it on. If it drops or rewrites part of Microsoft's answer, the tool finds a header missing, which is exactly error 12150.

1. Disconnect any VPN and close ad blockers or parental filters that run as programs.
2. Open Settings > Network & internet > Proxy. Under Manual proxy setup, select Edit next to Use a proxy server, turn it Off and Save. On Windows 10 the page is Settings > Network & Internet > Proxy.
3. Right-click Start and open Terminal (Admin) on Windows 11 or Windows PowerShell (Admin) on Windows 10.
4. Run the first command below. Direct access (no proxy server). is the normal answer.
5. If a proxy server is listed, run the second command to remove it.
6. In your security app, turn off only the setting often called HTTPS scanning, SSL/TLS filtering or scan encrypted connections. Protection itself stays on.
7. Run the tool or Check for updates again.

netsh winhttp show proxy
netsh winhttp reset proxy

Fix 3. Skip the tool: upgrade from the Windows ISO file

30 to 90 minutesRead the warningThe Media Creation Tool or the assistant still fails, and you want to upgrade or repair Windows with an in-place install.

The ISO is one large file that your browser downloads, so the tool's own download step, where 0x80072F76 appears, is never used. Setup from the ISO keeps your files and apps when you choose to.

1. On Microsoft's software download page for Windows 11, go to the disk image (ISO) section, choose Windows 11, your language and the 64-bit download.
2. Make sure drive C has at least 20 GB free. Microsoft support names 20 GB for a 64-bit upgrade.
3. In File Explorer, right-click the ISO file in Downloads and select Mount.
4. Open the new DVD drive and double-click setup.exe, then select Yes in User Account Control.
5. When Setup asks what to keep, choose Keep personal files and apps.
6. Let the PC restart several times until you see the sign-in screen.

The same ISO route helps with other Media Creation Tool codes too. For the error 0x80070006 - 0x90018, see our Media Creation Tool guide.

Fix 4. Reinstall Windows through Windows Update and keep your files

30 to 60 minutesRead the warningYou ran the Media Creation Tool to refresh or repair Windows, not to change the version.

Readers on Microsoft's Q&A hit 0x80072f76 - 0x20016 while trying to start Windows 10 fresh with the setup tool. Windows 11 has a built in way to reinstall the current version through Windows Update, with no separate tool to download.

1. Open Recovery in Settings. Open Settings > System > Recovery. Next to Fix problems using Windows Update, select Reinstall now. This keeps your apps, files and settings.

   

2. Start the reinstall. Choose whether the PC may restart on its own 15 minutes after the installation, then select OK.
3. Wait and restart. Windows Update downloads and installs a repair copy of your current Windows version. Keep the PC plugged in and online, and restart it when asked.
4. If that did not help: Reset PC. Back in Settings > System > Recovery, next to Reset this PC, select Reset PC. This keeps your personal files but removes installed apps and settings.
5. Choose Keep my files. Select Keep my files. Do not select Remove everything.

   

6. Choose where Windows comes from. Select Cloud download to download a fresh copy of Windows, or Local reinstall to use the files already on the PC (faster, but may not include the latest updates).
7. Reset. Review the summary and select Reset. The PC restarts several times.

These steps were written for Windows 11 22H2 and later. The full page with the other versions and what each result means: Reinstall Windows without losing files

On Windows 10 22H2 this button does not exist. Use the ISO with Fix 3, or Settings > Update & Security > Recovery > Reset this PC with Keep my files.

Fix 5. Run the tool from a clean boot with extra hardware unplugged

15 minutesLow riskFixes 1 to 3 did not help, or you suspect a program that starts with Windows.

Microsoft support's list for this code was: free space, unplug hardware you do not need, remove third-party security software and do a clean boot. A clean boot starts Windows with only Microsoft services, so a program that changes the download cannot run.

1. Open System Configuration. Select Search on the taskbar, type msconfig and select System Configuration from the results.
2. Hide Microsoft services. On the Services tab, select the Hide all Microsoft services check box. Only services from other companies stay in the list.
3. Disable the remaining services. Select Disable all, then select Apply.
4. Open Task Manager. On the Startup tab of System Configuration, select Open Task Manager.
5. Disable the startup apps. On the Startup apps tab in Task Manager, select each item whose status is Enabled and select Disable. Write down or take a screenshot of the items you disable: you need the list to turn them back on.
6. Confirm the changes. Close Task Manager. On the Startup tab of System Configuration, select OK.
7. Restart and test. Restart the PC. Windows now starts in a clean boot environment: try again the thing that failed (run the app, install the update, uninstall the program).

These steps were written for Windows 11 25H2 and 26H2. The full page with the other versions and what each result means: How to perform a clean boot in Windows

1. Unplug USB drives, docks and other devices the PC does not need. Leave the USB drive for the tool only if you are making install media.
2. In the clean boot, run the tool as administrator, as in Fix 1.
3. If it still fails, pause your antivirus for this one attempt only: Turn off Microsoft Defender protection for a moment
4. Turn the antivirus back on and return to a normal start afterwards.

Fix 6. Run the Windows Update troubleshooter

5 minutesNo riskThe code shows in Settings > Windows Update, not in a setup tool.

The troubleshooter restarts the update services and resets their settings. It helps when Windows Update itself is stuck, but it cannot fix the Media Creation Tool.

1. Open Troubleshoot settings. Select Start > Settings > System > Troubleshoot.
2. Open the list of troubleshooters. Select Other troubleshooters.

   

3. Run the Windows Update troubleshooter. Under Most frequent, select Run next to Windows Update. The Get Help app opens and starts the checks.

   

4. Read the result. Wait until Get Help finishes. If it found and fixed a problem, it says so and asks whether this solved the problem. Answer the question so it can offer the next step.

   

5. Restart the PC. Restart when the troubleshooter finishes, even if it does not ask you to.
6. Check for updates again. Select Start > Settings > Windows Update > Check for updates, and install the updates it finds.

These steps were written for Windows 11 (screenshots: 26H2). The full page with the other versions and what each result means: Run the Windows Update troubleshooter

Fix 7. Reset the Windows Update components

15 minutesLow riskThe troubleshooter did not help and the same update keeps failing.

A broken partial download can stay in the update cache and fail again on every try. Renaming SoftwareDistribution and catroot2 makes Windows download the update from the start.

1. Open Command Prompt as administrator. Type cmd in the search box, right-click Command Prompt and select Run as administrator. Select Yes when Windows asks for permission.
2. Stop the update services. Type the commands below and press Enter after each one. If Windows says that other services depend on Cryptographic Services, it stops them too. A message that a service is not started is fine.

   net stop wuauserv
   net stop bits
   net stop cryptsvc

3. Delete the download queue files. This clears the list of downloads that the Background Intelligent Transfer Service keeps. If Windows says it cannot find the files, continue.

   del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat"

4. Rename the update cache folders. Renaming keeps a copy in case you need it; Windows creates new, empty folders when the services start again. If you get Access is denied, a service is still running: repeat the previous step.

   ren %systemroot%\SoftwareDistribution SoftwareDistribution.old
   ren %systemroot%\System32\catroot2 catroot2.old

5. Start the services again. Type the commands below and press Enter after each one. The requested service has already been started is fine: Windows started it on its own.

   net start cryptsvc
   net start bits
   net start wuauserv

6. Restart and check for updates. Restart the PC. Then select Start > Settings > Windows Update > Check for updates. The first check can take longer than usual because everything is downloaded again.

These steps were written for Windows 11 and Windows 10 (the steps are the same). The full page with the other versions and what each result means: Reset Windows Update components

Fix 8. Install the failed update from the Microsoft Update Catalog

10 minutesLow riskOne KB update keeps failing with 0x80072F76 in Windows Update.

The Catalog gives you the standalone package of the update, downloaded by your browser. Windows Update's own download, where the error happens, is not used.

1. Open Settings > Windows Update > Update history and copy the KB number of the update that failed.
2. Check your system type in Settings > System > About, for example 64-bit operating system, x64-based processor.

1. Check the processor type. Open Settings > System > About and look at System type: an x64-based PC needs the x64 file, an ARM-based PC (for example Snapdragon) needs the arm64 file.
2. Search the catalog. Open the Microsoft Update Catalog at catalog.update.microsoft.com in your browser, type the KB number (for example KB5124010) in the search box and press Enter.
3. Pick the right row. Find the row whose title names your Windows version and your processor type (x64-based or arm64-based) and select Download on that row.

   

4. Download every file listed. A window lists one or more .msu links. Download all of them into one empty folder, for example C:\packages. On Windows 11 24H2 and later the list can include earlier checkpoint updates that the new one needs.
5. Install a single file. If there is only one file, double-click it and confirm the installation in the Windows Update Standalone Installer.
6. Install several files with DISM. If there are several files, open an elevated Terminal or Command Prompt and run DISM with the newest file. DISM finds the other files in the same folder and installs them in the right order.

   DISM /Online /Add-Package /PackagePath:C:\packages\<newest-file>.msu

7. Restart. Restart the PC when the installation finishes, then run winver again: the OS build should have changed.

These steps were written for Windows 11 24H2 and later; Windows 10 22H2. The full page with the other versions and what each result means: Install an update from the Microsoft Update Catalog

If error 0x80072F76 is still there

For Windows Update, build the readable log with the PowerShell command below. It writes WindowsUpdate.log to your desktop. Search it for 80072F76 and read the lines just above the hit: they show which address Windows tried to reach.

Get-WindowsUpdateLog

For the Media Creation Tool, the hidden folder C:\$Windows.~WS and the folder C:\$WINDOWS.~BT can hold Setup's own logs. We could not confirm from a source we read today which log file the tool writes for this code, so look for the newest .log files there and search them for 80072F76.

For support, send the full code with its second part (such as 0x20017), the tool and its version, your Windows version from Settings > System > About, and the output of netsh winhttp show proxy. This error is not a hardware fault and not a licence problem.

How to keep error 0x80072F76 from coming back

Frequently asked questions

What does error code 0x80072F76 mean?

It means a reply from the server came back without a header Windows needed. The code is WinINet error 12150, ERROR_HTTP_HEADER_NOT_FOUND, which Microsoft describes as "The requested header could not be located." In practice the download of setup or update files was cut or changed on the way. An old or blocked copy of the setup tool, a proxy, a VPN or HTTPS scanning are the usual reasons. Start with Fix 1 and Fix 2.

Is 80072F76 the same as 0x80072F76?

Yes. Some windows show the code without the 0x prefix, as 80072F76, and small letters, as in 0x80072f76, make no difference. Searches such as error windows update 80072f76 and error code 0x80072f76 are about the same error. When the code has a second part, such as 0x80072F76 - 0x20017, the first part is the same WinINet error and the second says at which step the setup tool stopped.

How do I fix Media Creation Tool error 0x80072F76 - 0x20017?

Delete the old copy of the tool, download it again from Microsoft, tick Unblock in its Properties if the box is there, and run it as administrator. That is Fix 1 and it takes five minutes. If the error comes back, remove any proxy, VPN or HTTPS scanning with Fix 2. If the tool still fails, skip it: download the Windows 11 ISO and run setup.exe from it, as Fix 3 shows.

What is 0x80072F76 - 0x20016?

It is the same download error with a different second code. Readers on Microsoft's Q&A reported it from the Windows 10 setup tool, including when they tried to start Windows fresh. Microsoft support asked whether the tool was damaged and suggested free space, unplugging extra hardware and a clean boot. Use Fix 1 first. If you only want to refresh Windows, Fix 4 reinstalls it without the tool.

Why does the Windows 11 Installation Assistant show 0x80072F76?

The Installation Assistant downloads Windows 11 the same way the Media Creation Tool does, so the same WinINet error can stop it. Download a fresh copy and run it as administrator (Fix 1), then check for a proxy or VPN (Fix 2). If it keeps failing, the ISO route in Fix 3 does the same upgrade without the assistant's download step.

Does 0x80072F76 appear in Windows Update too?

Yes, less often. Then the code is next to an update in Settings > Windows Update or in Update history. Check the proxy and VPN with Fix 2 first, because the cause is still the download. After that, run the troubleshooter (Fix 6), reset the update components (Fix 7) or install the KB update by hand from the Microsoft Update Catalog (Fix 8).

What is error 0x80072F7D in Windows Update?

It is a different code from the same WinINet library. 0x80072F7D is error 12157, ERROR_INTERNET_SECURITY_CHANNEL_ERROR, which points at the secure connection on the PC rather than at a missing header. It shows up mostly on old Windows versions. Check the date, time and proxy settings first. This page is about 0x80072F76, so the fixes here only overlap in Fix 2.

What about error code 0x80072F8F?

0x80072F8F is another WinINet code, not a spelling of 0x80072F76. We did not read a Microsoft source on it for this page, so we do not describe its meaning here. If your screen shows 0x80072F8F, the proxy and VPN check in Fix 2 is still a safe first step, and checking that the date and time are set automatically costs nothing.

Can my antivirus or VPN cause 0x80072F76?

Yes. A VPN, a proxy or a security app that scans HTTPS traffic sits between your PC and Microsoft's servers. If it drops or changes part of the answer, the setup tool sees a header missing and stops with this code. Disconnect the VPN and turn off only the HTTPS scanning setting for one try, as Fix 2 describes. Never leave the protection itself off.

Is 0x80072F76 a hardware problem?

No. The code describes a download reply, not a disk, memory or other part. It is also not a licence or activation problem. If the error appears on one network only, the network is involved, so try another network such as a phone hotspot. If it appears everywhere, the tool or a program on the PC is the cause, which Fixes 1, 2 and 5 cover.