Windows Update error 0x800f0845: how to fix it

What 0x800f0845 means

Codes starting with 0x800f08 come from the servicing stack, the part of Windows that unpacks updates into the component store. Microsoft’s error tables give names to many of them, such as CBS_E_STORE_CORRUPTION for 0x800f0831 and CBS_E_SOURCE_MISSING for 0x800f081f. We checked those tables on Microsoft Learn and 0x800f0845 isn’t in any of them.

So any site that gives you a precise official definition is guessing. What is consistent across user reports is the pattern: an update downloads, fails during install, and Windows Update shows the code next to it. For the closely related codes, Microsoft’s fix is to repair the component store, and that is the sensible starting point here too. That’s our inference, not a Microsoft statement.

Where the code first showed up

The code became widely known in January 2018 with KB4056892, the Meltdown and Spectre update for Windows 10 version 1709. Microsoft acknowledged that a small subset of older AMD processors could end up unbootable after that update, paused it for those devices, and shipped the fix as KB4073290. Microsoft’s pages describe the boot problem but never mention 0x800f0845; the link between the two comes from news sites and forum reports at the time.

Since then the code has turned up on many other updates. A 2024 Parallels support article tied it to Windows 11 Insider updates failing inside Parallels virtual machines, which Microsoft later addressed. Users on Microsoft Q&A have also reported it on recent Windows 10 cumulative updates. If you see it today, you’re almost certainly not dealing with the 2018 AMD problem.

Before you start

• Create a restore point, since some steps below rename system folders.
• Make sure you have plenty of free space on the system drive; cumulative updates need room to unpack.
• If a third-party antivirus is installed, it can be worth disabling it temporarily while you retry. Users report it helps in some cases, though Microsoft doesn’t list it as a cause for this code.
• Write down the KB number of the failing update from Settings > Windows Update > Update history.

Fix 1: Reset Windows Update the way Microsoft does

Many guides rename the whole SoftwareDistribution folder. Microsoft’s own reset steps are narrower: they stop the services, clear the BITS queue files, and rename only the data store, the download cache and the catalog folder. Open Command Prompt as administrator and run:

net stop bits
net stop wuauserv
net stop cryptsvc
Del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat"
Ren %Systemroot%\SoftwareDistribution\DataStore DataStore.bak
Ren %Systemroot%\SoftwareDistribution\Download Download.bak
Ren %Systemroot%\System32\catroot2 catroot2.bak
net start bits
net start wuauserv
net start cryptsvc

Restart, then check for updates. Microsoft’s page lists further steps (re-registering DLLs, resetting Winsock, and resetting service permissions with sc.exe sdset). It warns that the permissions step overwrites the services’ security settings, so we’d only go that far if everything else here fails.

Fix 2: Repair the component store

In the same administrator window, run DISM first and SFC second:

DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow

DISM compares the component store against Windows Update and replaces damaged files; SFC then fixes protected system files using that repaired store. DISM can appear stuck at one percentage for a long while; give it time before assuming it has hung. If DISM can’t download what it needs, Microsoft documents pointing it at a mounted Windows image with /Source: and /LimitAccess. Our sfc /scannow guide explains what each result message means.

Fix 3: Read CBS.log for the failing package

If the update still fails, the servicing log usually says why. Copy C:\Windows\Logs\CBS\CBS.log to your desktop, open it in Notepad and search for 0x800f0845. The lines just above the match name the package that failed. If they mention a file Windows couldn’t find or verify, run Fix 2 again; if they show a different error code, search for that code instead, because it’s the more specific one.

Fix 4: Install the update by hand

Search the Microsoft Update Catalog for the KB number you noted, and download the file that matches your Windows version and architecture (x64 or Arm64). Updates arrive as .msu files: double-click to install, or run wusa.exe C:\path\to\update.msu from an admin prompt. The standalone installer goes through the same servicing stack, so it may fail the same way, but it rules out a download problem. Afterwards, check Windows Update again for anything else that’s queued.

Fix 5: Repair Windows without losing files

When the component store is too damaged to patch, reinstalling the current version replaces it.

• Windows 11: go to Settings > System > Recovery, find Fix problems using Windows Update and select Reinstall now. Microsoft says this keeps apps, files and settings. It needs Windows 11 version 22H2 or later with the February 2024 optional update or newer, the PC must stay plugged in and online, and the option can be missing on work or school PCs.
• Windows 10: run the Media Creation Tool from Microsoft, choose Upgrade this PC now and keep personal files and apps. Windows 10 reached end of support in October 2025, so updates after that require Extended Security Updates.

Back up important files first, even though both options are designed to keep them.

If the update crashes and rolls back

Some users describe a blue screen during the restart, then We couldn’t complete the updates. Undoing changes, and finally 0x800f0845 in Windows Update. That points less at the update files and more at something the update touches on boot, often a driver. That is our reading of the reports, not a Microsoft diagnosis. Update chipset, storage and graphics drivers from the PC or motherboard maker, then retry. Our guide to error 0x800f0922 covers other install failures that end in a rollback.

Fixes to skip

Two shortcuts circulate on other sites. Some give a DISM /Remove-Package command with a Windows 7 package name, which doesn’t exist on Windows 10 or 11 and will just return an error. Others say to right-click an .inf file from the Update Catalog to install it; current updates are .msu or .cab packages, not .inf files.

Related guides

• Windows Update error 0x800f0831: how to fix it
• Error 0x800f081f: how to fix it in Windows 11 and 10
• Windows Update error 0x800f0988: how to fix it
• 0x800f0922: how to fix this Windows Update error in Windows 11 and 10
• How to run sfc /scannow in Windows 11 and 10 (and read the results)

Official sources

• Additional resources for Windows Update (Microsoft Learn)
• Fix Windows Update corruptions and installation failures (Microsoft Learn)
• Fix issues by reinstalling the current version of Windows (Microsoft Support)