How to fix Windows update error 0x800f0987?

Error 0x800f0987 appears when an update has downloaded and almost installed, but Windows cannot rebuild one of the brand new files the package brings, so it undoes everything. Restart and retry once, because Windows repairs itself after this failure. If the code returns, repair the component store with DISM, then install the update by hand.

Facts checked on 16 October 2026. Steps written for Windows 11 (25H2 and 26H2), Windows 10 22H2.

What Windows update error 0x800f0987 means

0x800f0987 is a code of the Windows servicing stack, the part of Windows that installs updates. Microsoft lists it as 0x800F0987, PSFX_E_NULL_DELTA_HYDRATION_FAILED: "package corruption or integration failure". The download is already over when it appears, which is why the update seems to install fully and then fails.

The name describes one exact step. A cumulative update does not carry every file whole. Files that existed in the base version of Windows come as small differences, called deltas. Files that are new since the base have nothing to start from, so the package carries them as null differentials: Microsoft describes these as "slightly compressed and optimized" copies of the full files.

Before it installs anything, Windows rebuilds, or hydrates, every full file it needs. Null compressed files are expanded and kept in the component store, C:\Windows\WinSxS, under an n folder. When one of them cannot be expanded or checked, hydration fails with 0x800f0987 and the whole update is rolled back.

Why Windows update error 0x800f0987 appears

Microsoft ties this whole group of codes to damage in the servicing stack: missing files, an invalid configuration or broken metadata. For 0x800f0987 the damage sits either in the null compressed piece of the update or in the component store that receives it. The table ranks the cases from the most to the least common and names the fix for each.

How to fix Windows update error 0x800f0987

Fix 1 lets the built-in corruption repair finish its work and costs one restart. Fix 2 to Fix 4 repair the component store, take the full package from the catalog and clear the download cache. Fix 5 is a short test for other software. Fix 6 reinstalls Windows over itself and keeps your apps and files, which Microsoft names as the reliable answer for this group of codes.

Fix 1. Restart the PC and retry the update once

10 to 20 minutesNo riskEveryone, first, and above all after the first failure.

Microsoft describes a lazy automatic corruption repair: when hydration of a file fails, Windows notes the damaged piece, lets the update fail, then repairs the list from Windows Update. After that, Microsoft writes, the installation "will succeed on the next attempt".

1. Wait until the Undoing changes screen has finished and Windows has started normally.
2. Leave the PC online for 10 minutes, so the automatic repair can download the clean copies it needs.
3. Select Start > Power > Restart. Use Restart, not Shut down, because Fast Startup can skip pending work at shut down.
4. On Windows 11 open Settings > Windows Update. On Windows 10 open Settings > Update & Security > Windows Update.
5. Select Retry next to the failed update, or Check for updates if it is no longer listed.
6. If a newer cumulative update is offered, install that one: it contains the failed one.
7. Open Update history and check that the update reads Successfully installed.

Fix 2. Repair the component store with DISM and SFC

20 to 40 minutesNo riskThe same update failed again after Fix 1, or SFC reports damaged files.

DISM RestoreHealth is the manual form of the corruption repair Microsoft describes for hydration failures. It checks the component store against clean copies from Windows Update and replaces damaged files, which is where the null compressed files are kept. SFC then repairs the system files that depend on the store.

1. Open an elevated command window. Right-click Start and select Terminal (Admin), or type cmd in the search box, right-click Command Prompt and select Run as administrator. Select Yes when Windows asks for permission.
2. Run DISM first. Type the command below and press Enter. DISM downloads clean copies of damaged components from Windows Update, so it can take several minutes. Wait until it says The operation completed successfully.

   DISM.exe /Online /Cleanup-Image /RestoreHealth

3. Run System File Checker. In the same window, type the command below and press Enter. Do not close the window until the verification reaches 100%.

   sfc /scannow

4. Read the result and restart. Compare the last message with the table below this guide, then restart the PC so that repaired files are loaded.

These steps were written for Windows 11 24H2 and 25H2. The full page with the other versions and what each result means: Run DISM and SFC to repair Windows system files

If DISM stops with a message that the source files could not be found, Windows Update cannot serve as the repair source on this PC. Mount an ISO of the same Windows version, edition and language: right-click the ISO, select Mount and note the drive letter. Then run, with your letter in place of D::

dism /Get-WimInfo /WimFile:D:\sources\install.wim
DISM /Online /Cleanup-Image /RestoreHealth /Source:wim:D:\sources\install.wim:1 /LimitAccess

Use the index of your edition from the first command in place of the last 1. When the ISO holds install.esd, write that name and esd: in place of wim:.

Fix 3. Install the failing update by hand from the Microsoft Update Catalog

20 to 40 minutesLow riskOne KB keeps failing in Windows Update while other updates install.

The catalog file is the full standalone package of the update, the .msu file administrators deploy. It carries all its differentials in one piece, so it rules out a damaged copy of the package. When it fails with the same code, you know the fault is in your component store.

1. Check your Windows version. Press Windows key + R, type winver and press Enter. Note the version (for example 25H2) and the OS build.
2. Find the KB number. Open Settings > Windows Update. A failed or pending update is listed with its KB number; earlier ones are under Update history.
3. 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.
4. 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.
5. 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.
6. 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.
7. Install a single file. If there is only one file, double-click it and confirm the installation in the Windows Update Standalone Installer.
8. 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

9. 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

Fix 4. Reset the Windows Update components and the download cache

10 minutesLow riskThe update fails at the same percentage on every try, or the catalog file would not start.

Windows Update reuses the files it already downloaded into SoftwareDistribution at every retry. If the null compressed piece in that copy is damaged, each retry fails the same way. Renaming the folder and catroot2 makes Windows download the package again from zero.

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 5. Install the update in a clean boot

20 minutesLow riskCleaning, tuning or third-party security software is installed, and Fix 1 to Fix 4 failed.

Microsoft does not link 0x800f0987 to other software, so this is a test, not a likely cure. It costs far less than the repair reinstall: if a tool that locks or scans files in the component store is in the way, the update installs with only Microsoft services running.

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. After the restart, open Windows Update and install the failed update.
2. Open System Configuration again, select Normal startup on the General tab and turn the startup apps back on in Task Manager.
3. Restart. If the update installed only in the clean boot, update or remove the cleaning or security tool you had.

Fix 6. Reinstall Windows over itself and keep apps and files

1 to 2 hoursLow riskEvery fix above ended with 0x800f0987, or the code returns with each month's update.

Microsoft lists 0x800F0987 among the codes of severe servicing stack corruption where an in-place upgrade is "the only reliable resolution". It reinstalls Windows "while preserving your data, applications, and settings" and builds a new component store, so the next updates find every file they need.

On Windows 11 the reinstall is built into Settings as Fix problems using Windows Update:

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.

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

1. On Windows 10 22H2, or when the Settings option fails, download the Media Creation Tool for your Windows from Microsoft and run it.
2. Select Yes in the User Account Control prompt and accept the licence terms.
3. Select Upgrade this PC now and Next, then wait while the tool downloads Windows.
4. On the Ready to install screen, check that Keep personal files and apps is listed. If not, select Change what to keep.
5. Select Install and leave the PC on until Windows starts again.

Windows 10 left support on 14 October 2025. If your PC runs Windows 10 and its hardware allows, the repair reinstall is a good moment to move to Windows 11 instead.

If error 0x800f0987 is still there: the log and what to send

The cause is written in the servicing log. Microsoft points to three files for this group of codes, all in C:\Windows\Logs\CBS: CBS.log, CbsPersist_*.log and CbsPersist_*.cab. Read them before you reset the PC or contact support.

1. Press Win + R, type %windir%\Logs\CBS and press Enter.
2. Copy CBS.log to the Desktop and open the copy in Notepad, so the original stays untouched.
3. Press Ctrl + F and search for 0x800f0987, then for NULL_DELTA_HYDRATION.
4. Read the lines just above the last hit. They usually name the component and the package that Windows tried to hydrate.
5. If the attempt was days ago, open the newest CbsPersist_ file in the same folder. A .cab file opens like a folder in File Explorer.

How to keep error 0x800f0987 from coming back

The component store is the part that breaks, so prevention means leaving it to Windows. Free space the supported way: Disk Cleanup with Clean up system files removes old update files without touching the files the next update needs.

Frequently asked questions

What does error 0x800f0987 mean?

It means Windows downloaded an update but could not rebuild one of the files the update adds for the first time. Microsoft's name for the code is PSFX_E_NULL_DELTA_HYDRATION_FAILED, described as package corruption or integration failure. New files travel as null differentials, compressed copies of the full file. Windows expands them before it installs, and when that fails, it rolls the update back. The cause is damage in the package copy or in the component store.

Why does the update install fully and then fail with 0x800f0987?

Because the failure happens at the end of the work. Windows downloads the package, checks it applies and then hydrates every full file it needs before the final install. 0x800f0987 is raised in that hydration step, so the progress bar has already gone far. Windows then undoes all changes, which is the Undoing changes screen you may see during the restart. Nothing was installed, so the update is offered again.

How do I fix 0x800f0987 on Windows 11?

Restart the PC, open Settings > Windows Update and select Retry once (Fix 1). If it fails again, run DISM RestoreHealth and then sfc /scannow in an elevated Command Prompt (Fix 2). Next, install the KB from the Microsoft Update Catalog (Fix 3) and reset the update cache if the install stops at the same point (Fix 4). When the code still returns, use Fix problems using Windows Update in Settings > System > Recovery.

How do I fix 0x800f0987 on Windows 10?

The fixes are the same as on Windows 11, with the Windows 10 menu names. Retry in Settings > Update & Security > Windows Update, then run DISM and SFC, then install the KB from the catalog. For the repair reinstall, use the Media Creation Tool and choose Upgrade this PC now. Windows 10 left support on 14 October 2025, so if your hardware allows, moving to Windows 11 is the better long-term answer.

Is it safe to keep retrying the update?

One retry after a restart is worth it, because Windows repairs damaged pieces after this failure and the next attempt can succeed. Retrying many times is safe but pointless: if the code returns twice, the automatic repair could not fix the damage, and each attempt only costs time and another rollback. Move on to DISM and SFC in Fix 2. Do not turn the PC off during the rollback screen.

Is 0x800f0987 the same as 0x800f0988 or 0x800f0989?

No. They are neighbours in the same group of servicing errors, and each fails at a different step. Code 0x800F0987 is a failed hydration of a null differential, a file that is new since the base version. Code 0x800F0988 is an invalid delta combination. Code 0x800F0989 is a missing reverse delta, which our guide to error 0x800f0989 explains. The quick fixes overlap. For all three, Microsoft treats the in-place upgrade as the reliable answer when the quick fixes fail.

What about Windows Update error 0x800f0247?

That code is not related to this one, although it starts the same way. Microsoft's name for 0x800F0247 is SPAPI_E_DRIVER_STORE_ADD_FAILED: a problem while adding a driver to the driver store. It is seen when a driver offered through Windows Update fails, not with cumulative updates. The fixes on this page are aimed at the component store, so for 0x800f0247 look at the driver named next to the code in Update history.

Does the Windows Update troubleshooter fix 0x800f0987?

Rarely. The troubleshooter checks the update services and settings and clears stuck downloads. 0x800f0987 happens later, while Windows hydrates files for the component store, and the troubleshooter does not repair that store. You can still run it in a few minutes to rule out a stopped service: Run the Windows Update troubleshooter. If it finds nothing, as the old advice also said, carry on with the fixes on this page.

Will I lose files when I fix 0x800f0987?

No fix on this page deletes your personal files. Fix 1 to Fix 5 only touch updates, system components, the download cache and startup settings. Fix 6 reinstalls Windows but keeps your apps, files and settings when Keep personal files and apps is selected. Back up important files before Fix 6 anyway. Only Reset this PC, in the section after the fixes, removes installed apps.

Should I turn off my antivirus to install the update?

Not as a fix. Microsoft does not tie this code to security software, and the damage it describes sits in the update package or the component store. If the clean boot in Fix 5 points to a security tool, pause its protection for one install only and turn it back on right after: Turn off Microsoft Defender protection for a moment. Microsoft Defender never has to be removed for an update to install.