Fixes / Windows · Checked

Windows Update error 0x80240034: what it means and how to fix it

Short answer

Error 0x80240034 is Windows Update's WU_E_DOWNLOAD_FAILED code. It means the update did not finish downloading, often because files in the update cache are damaged or the download was blocked. The most likely fix is to stop the Windows Update and BITS services, rename the SoftwareDistribution\Download and DataStore folders, restart the services, and select Check for updates again.

What this message means

Microsoft's Windows Update error reference lists 0x80240034 as WU_E_DOWNLOAD_FAILED, "Update failed to download." Windows found the update and started to fetch it, but the download stopped before a complete, verified copy was saved. The update usually sits at "Downloading 0%" or partway through, then shows "Download error - 0x80240034" in Settings > Windows Update. This code does not mean your Windows installation is broken. It is a download problem, not an install problem. That is why clearing the download cache, fixing the network path or getting the same update from another source usually solves it. It can affect monthly cumulative updates, Defender definition updates, .NET updates and feature updates.

Common causes

CauseHow to tell
Damaged or partial files in the Windows Update cache (C:\Windows\SoftwareDistribution)The same update fails again and again with 0x80240034, often stuck at the same percentage, while other updates in the list download fine.
The Background Intelligent Transfer Service (BITS) or Windows Update service is stuck or has a corrupt job queueEvery download sits at 0% or "Pending download". In services.msc, Background Intelligent Transfer Service or Windows Update shows as stopped, or is stuck on Starting.
Unstable connection, a metered connection, VPN, proxy, or third-party antivirus/firewall interrupting the downloadDownloads start and then fail partway through, or the error only happens on one network (for example office VPN or hotel Wi-Fi) and not on another.
Not enough free disk space for the download and unpackingIn File Explorer, the C: drive bar is red or shows only a few GB free. Feature updates need at least 20 GB free on 64-bit Windows.
Damaged Windows system files or component store affecting the update agentSeveral different updates fail with various codes, not just 0x80240034, and the Windows Update troubleshooter reports problems it cannot fix.
On company PCs managed by WSUS: the server cannot serve that file typeOnly certain updates fail (often ones delivered as .exe, such as the Malicious Software Removal Tool KB890830 or SQL Server updates). .cab-based updates download normally, and the device gets updates from a WSUS server rather than directly from Microsoft.

How to fix it

1. Restart, then run the Windows Update troubleshooter

Windows 11 and Windows 10 (menu paths differ)

  1. Restart the PC (use Restart, not Shut down) so any pending update actions can finish.
  2. Windows 11: go to Start > Settings > System > Troubleshoot > Other troubleshooters, then select Run next to Windows Update. On newer builds this opens the Get Help app.
  3. Windows 10: go to Start > Settings > Update & Security > Troubleshoot > Additional troubleshooters, then select Windows Update > Run the troubleshooter.
  4. Apply any fixes it offers, then restart again.
  5. Open Settings > Windows Update and select Check for updates (Windows 11) or Settings > Update & Security > Windows Update > Check for updates (Windows 10).

2. Check your connection, disk space and security software

  1. Disconnect any VPN and switch to a stable wired or home Wi-Fi connection if you can.
  2. Make sure the connection is not set as metered. Windows 11: Settings > Network & internet > Wi-Fi (or Ethernet) > your network properties > Metered connection: Off. Windows 10: Settings > Network & Internet > Wi-Fi > your network > Set as metered connection: Off.
  3. Open File Explorer > This PC and check free space on C:. Free up space until you have at least 20 GB (64-bit) or 16 GB (32-bit) for feature updates, for example with Settings > System > Storage > Cleanup recommendations.
  4. If you use third-party antivirus or firewall software, pause it temporarily, try the update, then turn it back on.
  5. Select Check for updates again.

3. Clear the Windows Update download cache

  1. Select Start, type cmd, right-click Command Prompt and choose Run as administrator.
  2. Stop the update services by running these one at a time: net stop wuauserv, then net stop bits, then net stop cryptsvc
  3. Rename the cache folders: ren %systemroot%\SoftwareDistribution\DataStore DataStore.bak and ren %systemroot%\SoftwareDistribution\Download Download.bak
  4. Start the services again: net start bits, then net start wuauserv, then net start cryptsvc
  5. Restart the PC, open Windows Update and select Check for updates. Windows rebuilds the folders and downloads the update fresh. Your update history view may look empty afterwards. That is expected.

4. Repair system files with DISM and SFC

  1. Open Command Prompt as administrator.
  2. Run: DISM /Online /Cleanup-Image /RestoreHealth and wait for it to reach 100% (it can pause at 20% or 62% for several minutes).
  3. Run: sfc /scannow
  4. Restart the PC and try Windows Update again.

5. Install the update manually from the Microsoft Update Catalog

  1. In Settings > Windows Update > Update history, note the KB number of the failed update (for example KB5043145).
  2. Check your Windows version and architecture in Settings > System > About (look at Edition, Version and System type).
  3. Go to catalog.update.microsoft.com, search for the KB number and choose the entry that matches your version and architecture (x64, arm64).
  4. Select Download and click the .msu link to save it.
  5. Double-click the downloaded file to install it, then restart.
  6. For a failed feature update (for example a new yearly version), use the Windows 11 Installation Assistant from microsoft.com/software-download/windows11 instead.

6. Fix WSUS so it can serve .exe updates

Managed networks using WSUS (IT administrators)

  1. Confirm the failing updates are .exe-based (for example KB890830 or SQL Server cumulative updates) while .cab updates succeed.
  2. On the WSUS server, open Internet Information Services (IIS) Manager and select the WSUS Administration site.
  3. Open MIME Types and check that .exe exists. If not, add it with MIME type application/octet-stream.
  4. On an affected client, restart the Windows Update service and scan for updates again.

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Still not fixed?

If the download still fails, check C:\Windows\Logs\WindowsUpdate or run Get-WindowsUpdateLog in an administrator PowerShell window. The log creates WindowsUpdate.log on your desktop, and the lines around the failure show which URL or file was blocked. As a last resort, run an in-place repair upgrade. Windows 11: Settings > System > Recovery > Fix problems using Windows Update > Reinstall now (Windows 11 24H2 and later). You can also run setup.exe from a Media Creation Tool ISO and choose to keep files and apps. On a work or school PC, contact your IT department first, because WSUS, Intune or proxy policies may be blocking the download. Home users can contact Microsoft Support through the Get Help app.

Questions people ask

What does WU_E_DOWNLOAD_FAILED mean?

It is Microsoft's internal name for 0x80240034, officially described as "Update failed to download." Windows could see the update but could not save a complete copy of it.

Is it safe to delete the SoftwareDistribution folder?

Yes, as long as the Windows Update and BITS services are stopped first. It only holds temporary update files and scan data, and Windows recreates it automatically. You will lose the local update history list, not the installed updates.

Why does only one update fail with 0x80240034 while others install?

That usually points to a damaged partial download of that specific package, or, on company networks, a WSUS server that cannot serve its file type. Clearing the Download folder or installing that KB from the Microsoft Update Catalog normally solves it.

Can I ignore error 0x80240034?

You can pause it briefly, but the failed update is often a security or Defender update, so leaving it unfixed leaves the PC unpatched. Windows will keep retrying and showing the error until the download succeeds.

Does 0x80240034 mean my hard drive is failing?

Rarely. It is a download error, not a disk error. If SFC or DISM also report errors they cannot fix, check the drive's health with the manufacturer's tool or by running chkdsk C: /scan.

Sources

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