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Error 0x80009515 has no publicly documented, universal meaning from Microsoft. The correct fix depends on where it appears: Windows Update, an application installer or startup dialog, or a .NET Framework feature window. Record that context first, then work through Windows Update hygiene, the DISM and SFC repair commands, and the .NET Framework steps that match your Windows build. Windows 11 26H1 (build 28000) and later handle .NET Framework 3.5 differently from earlier releases, so using the wrong installation method can create another failure.
What does error 0x80009515 mean?
Microsoft does not define 0x80009515 in the Microsoft support and Learn material available for this issue, so it is not safe to label it as a specific .NET, Windows Update, registry, permissions or malware error. The dialog in which the code appears is the most useful clue. A code shown while adding a Windows feature requires a different source and command from the same code shown by a game launcher or a Windows upgrade.
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Before changing anything, write down the exact message, the program or installer name, the operation that failed, your Windows edition and build from winver, and whether the message appeared after Windows Update, a restart or a recent feature change. This record lets you return to the same operation after each repair and prevents applying an unrelated fix.
Capture the failure context
- Dialog text: copy the complete message, including any secondary code such as 0x800F081F, 0x800F0906 or 0x800F0907.
- Trigger: note whether you were updating Windows, installing or starting an application, enabling .NET Framework 3.5, or doing something else.
- Windows build: press
Win+R, enterwinver, and record the version and build number. - Timing: record whether the problem began immediately after an update, reboot, driver change or security-software change.
- Account: note whether the operation was run by a standard account or an administrator; DISM, SFC and feature installation require elevation.
What should I try first on Windows 11 or Windows 10?
Start with the low-risk Windows maintenance steps Microsoft recommends for update and upgrade failures. They clear common environmental blockers without assuming what 0x80009515 means.
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- Disconnect nonessential hardware. Shut down and unplug extra USB devices, docks, printers, external drives and other accessories. Leave the keyboard, mouse, display and network connection attached.
- Check free storage. In File Explorer, open This PC and verify that the Windows system drive has room for an update or component download. Remove or move large personal files if space is tight, but do not delete Windows folders manually.
- Install pending updates. On Windows 11, open Settings > Windows Update; on Windows 10, open Settings > Update & Security > Windows Update. Select Check for updates, install everything offered, restart when requested, and check again until no additional update is pending.
- Run the Windows Update troubleshooter. Windows 11 places it under Settings > System > Troubleshoot > Other troubleshooters; Windows 10 uses Settings > Update & Security > Troubleshoot where the troubleshooter is available. Microsoft notes that some newer automated troubleshooters cannot be launched manually, so use the entry presented by your edition rather than downloading an unofficial copy.
- Retry the original operation. Reproduce the same installer, update or feature action after the restart. If the code returns, continue with the branch that matches the dialog.
During a Windows upgrade, Microsoft also advises temporarily removing third-party security software if it is blocking installation. Treat that as a controlled diagnostic step: disconnect from untrusted networks if appropriate, use the product’s normal uninstall or pause procedure, and restore protection immediately after the test. Do not leave a computer unprotected as a permanent workaround.
How do I repair Windows system files safely?
Use the Deployment Image Servicing and Management (DISM) repair first, followed by System File Checker (SFC). These are general Windows repairs; a successful run does not prove that 0x80009515 itself represents file corruption.
Run DISM from an elevated Command Prompt
- Open Start, type
Command Prompt, right-click it and select Run as administrator. Approve the User Account Control prompt. - Enter the command below exactly and press
Enter:
DISM.exe /Online /Cleanup-image /RestorehealthDISM can pause at a percentage while it checks and repairs the component store. Leave the window open until it reports completion or an error. If it reports that the operation cannot be completed, copy the full message before closing the window; a missing or inaccessible repair source may require the installation-media procedure described later for .NET features.
Run SFC after DISM
- In the same elevated Command Prompt, run:
sfc /scannowWait for verification to reach 100 percent. Restart Windows regardless of whether SFC says it found and repaired files, then retry the operation that produced 0x80009515. If the code persists, return to the captured context instead of repeatedly running the same commands.
What if 0x80009515 appears during Windows Update or an upgrade?
Follow the general update checks first, then repair the Windows image and protected files. Keep nonessential peripherals disconnected and make sure the system drive has free space.
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Update-specific sequence
- Record the update name or version shown in Settings > Windows Update > Update history.
- Restart once after installing all currently offered updates, even if Windows did not request it.
- Run the Windows Update troubleshooter available in your Settings app.
- Run the elevated DISM and SFC commands shown above.
- Retry the update with third-party security software restored unless its vendor’s documented procedure requires otherwise.
Windows 10 reached end of support on October 14, 2025, according to Microsoft. A Windows 10 computer can still display installation errors, but it no longer receives routine support updates from Microsoft; plan a supported Windows 11 upgrade or another supported operating system rather than treating an old installation as permanently maintainable.
Could a missing .NET Framework version be causing the message?
It can, but the code alone does not establish that. Check the application’s requirements or the wording of the dialog. Older programs targeting .NET Framework 1.0 through 3.5 need the separate .NET Framework 3.5 feature, while current .NET Framework 4.x applications generally use the later 4.x release already supported by Windows.
Microsoft states, “The latest version of .NET Framework is 4.8.1.” .NET Framework 4.x is an in-place update, so a later 4.x release normally replaces an earlier 4.x release instead of being installed beside it. Windows 11 22H2 and later include .NET Framework 4.8.1, and Windows 10 22H2 can install 4.8.1 when the edition and servicing state support it.
How do I install .NET Framework 3.5 on my Windows build?
The correct method depends on the Windows 11 release. Windows 11 25H2 and earlier normally expose .NET Framework 3.5 as an optional Windows component; beginning with Windows 11 26H1 (build 28000), Microsoft says the feature is supplied only through a standalone installer.
| Windows release | Normal .NET 3.5 method | What you need |
|---|---|---|
| Windows 11 26H1, build 28000, and later | Use Microsoft’s standalone .NET Framework 3.5 installer for that release. | The installer that matches the installed release and administrator approval. |
| Windows 11 25H2 and earlier | Enable .NET Framework 3.5 (includes .NET 2.0 and 3.0) in Windows optional features, or use the matching DISM source when Windows requests one. | Internet access for component download, or a matching installation source. |
| Windows 10 22H2 and earlier supported builds | Enable the optional .NET Framework 3.5 feature through Windows Features or DISM. | Internet access or installation media from the same Windows build. |
Enable the feature through Windows Features
- Press
Win+R, typeoptionalfeatures, and pressEnter. - In Windows Features, select .NET Framework 3.5 (includes .NET 2.0 and 3.0). Do not select the 4.x entry unless the application specifically requires a different optional component.
- Select OK. If Windows asks to download files from Windows Update, allow the download on a trusted, working connection.
- Restart if Windows requests it, then launch the original application or installer again.
Do not use this optional-feature workflow on Windows 11 26H1 and later when Microsoft provides the standalone installer instead. Installing a package intended for another release can leave the feature unavailable or produce a different servicing error.
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How do I repair a damaged .NET Framework installation?
If several .NET Framework applications fail, the .NET dialog reports a framework problem, or installation repeatedly rolls back, use Microsoft’s .NET Framework Repair Tool. Microsoft says the tool applies recommended repairs automatically; it is intended to correct common installation and configuration problems rather than diagnose every application failure.
- Download the .NET Framework Repair Tool from Microsoft’s official support site and run it with an administrator account.
- Accept the tool’s license terms and allow it to apply the recommended repairs.
- Restart Windows if requested.
- Install the latest .NET Framework version supported by your Windows release, up to 4.8.1 where applicable, and retry the application.
If only one program fails while other .NET programs work, repair or reinstall that program as directed by its publisher after confirming its target framework. A framework repair cannot correct a broken application package, incompatible plug-in or damaged game data.
How do I fix .NET 3.5 source errors 0x800F081F, 0x800F0906 or 0x800F0907?
These codes specifically indicate that Windows could not obtain the files needed for the .NET 3.5 feature. Use an ISO or installation source that matches the installed Windows version and build; do not mix the sourcessxs folder from another release.
Prepare a matching source
- Obtain official Windows installation media that matches the edition and build shown by
winver. - Mount the ISO by right-clicking it in File Explorer and selecting Mount. Note the drive letter assigned to it, such as
X:. - Open the mounted drive and confirm that
X:sourcessxsexists and is readable. ReplaceX:below with your actual drive letter.
Enable .NET 3.5 from the source
- Open Command Prompt as administrator.
- Run the documented DISM command:
dism /online /enable-feature /featurename:netfx3 /all /source:X:sourcessxs /limitaccess- Wait for DISM to finish, restart Windows, and retry the original application or feature installation.
/limitaccess prevents DISM from switching to Windows Update while using the supplied source. If the command reports that files are missing, verify the drive letter, folder spelling and readability first. A mismatched, incomplete or inaccessible source is a common reason these documented feature-installation codes continue.
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Which troubleshooting path fits the trigger?
Use the following comparison to choose the shortest appropriate branch without assuming that 0x80009515 has one fixed definition.
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| Where the code appears | Start with | Administrator needed? | External source needed? |
|---|---|---|---|
| Windows Update or upgrade | Disconnect peripherals, install pending updates, restart, run the Windows Update troubleshooter, then DISM and SFC. | Yes for DISM and SFC; not usually for checking updates. | Not normally; security software may need temporary removal only when it blocks the upgrade. |
| Application installer or startup | Confirm the application’s required framework, repair Windows files, then repair .NET or reinstall the application as appropriate. | Often, especially for framework changes. | Only if the required .NET feature cannot download its files. |
| .NET 3.5 optional-feature dialog | Use the method for your Windows release; for source errors, use matching media and sourcessxs. |
Yes. | Online component download or a matching ISO, depending on the error. |
What should I do if the error remains?
Do not repeatedly enable and disable .NET features or run random registry cleaners. Return to the record you made at the start and narrow the failure:
- If only one installer fails, check that publisher’s documented Windows and .NET requirements and obtain a fresh installer from the publisher.
- If every Windows component operation fails, capture the complete DISM or SFC result and check that the Windows build, edition and installation source match.
- If the problem began immediately after an update or reboot, review Settings > Windows Update > Update history and note the exact update before considering removal through Microsoft’s supported recovery options.
- If a security product was paused for an upgrade test, restore it before normal browsing and gaming.
- If the computer is still on Windows 10, remember that Microsoft’s support ended October 14, 2025; moving to a supported release may be more appropriate than continuing to repair an unsupported installation.
Keep the original error text, build number and command results when seeking help from Microsoft or the application publisher. Those details are more actionable than the number 0x80009515 by itself.
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Is error 0x80009515 proof that my PC has a virus?
No. Microsoft has not assigned this code a malware meaning, and the number alone cannot identify an infection. Keep your existing security software current and investigate the program or Windows operation that displayed the code.
Can I install .NET Framework 4.8.1 beside an older 4.x release?
.NET Framework 4.x versions are in-place updates, so a supported 4.8.1 installation normally replaces the earlier 4.x version instead of creating a parallel copy. Applications targeting older 4.x releases generally continue to use the installed later runtime when compatibility is supported.
Why does .NET 3.5 ask for installation media when my internet works?
Windows may be unable to retrieve the optional component from its configured servicing source even when ordinary browsing works. A matching ISO with a readable sourcessxs folder supplies the component locally and avoids relying on that download path.
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Does Windows 11 26H1 install .NET Framework 3.5 through Optional Features?
Microsoft says Windows 11 26H1, build 28000, and later provide .NET Framework 3.5 through a standalone installer. The Optional Features procedure applies to Windows 11 25H2 and earlier, so check winver before choosing a method.
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsFrequently Asked Questions
Is error 0x80009515 proof that my PC has a virus?
No. Microsoft has not assigned this code a malware meaning, and the number alone cannot identify an infection. Keep your existing security software current and investigate the program or Windows operation that displayed the code.
Can I install .NET Framework 4.8.1 beside an older 4.x release?
.NET Framework 4.x versions are in-place updates, so a supported 4.8.1 installation normally replaces the earlier 4.x version instead of creating a parallel copy. Applications targeting older 4.x releases generally continue to use the installed later runtime when compatibility is supported.
Why does .NET 3.5 ask for installation media when my internet works?
Windows may be unable to retrieve the optional component from its configured servicing source even when ordinary browsing works. A matching ISO with a readable sources\sxs folder supplies the component locally and avoids relying on that download path.
Does Windows 11 26H1 install .NET Framework 3.5 through Optional Features?
Microsoft says Windows 11 26H1, build 28000, and later provide .NET Framework 3.5 through a standalone installer. The Optional Features procedure applies to Windows 11 25H2 and earlier, so check winver before choosing a method.
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