How to Enable .NET Framework 3.5 on Windows 11 — Every Method That Works in 2026

Windows 11 ships with .NET Framework 4.8.1 pre-installed. But thousands of older applications — legacy business software, CAD tools, older games, and desktop utilities built before 2015 — require .NET Framework 3.5 specifically. When you try to run these apps and see a prompt like “This application requires .NET Framework 3.5” or “You must install .NET Framework 3.5 to run this program,” Windows 11 needs a small configuration change to support them.

The good news: enabling .NET Framework 3.5 on Windows 11 takes about two minutes on a connected PC. There is no separate download required — the component is already inside Windows, just turned off.

The tricky part: the method changed in 2026. Starting with Windows 11 26H1 (build 28000), .NET Framework 3.5 is only available as a standalone installer — Windows Features and DISM cannot install it on those newer builds. If you are on Windows 11 25H2 or earlier, the standard Windows Features and DISM methods work perfectly. This guide covers all scenarios.

Before You Start — Check Your Windows 11 Version

The installation method depends on which Windows 11 version you are running.

Go to Settings, System, About. Look under Windows specifications for the Version and OS build fields.

Windows 11 25H2 and earlier (builds below 28000):

Use Method 1, 2, 3, or 4 from this guide. .NET Framework 3.5 is a built-in optional Windows component that can be enabled through Windows Features, DISM, or PowerShell.

Windows 11 26H1 (build 28000 and later):

The installation method changes at Windows 11 version 26H1, build 28000 — Windows Features and DISM cannot install it on these releases. Use the standalone installer from Microsoft’s download center instead. Skip directly to Method 5 in this guide.

What Is .NET Framework 3.5 and Why Do Apps Need It?

.NET Framework 3.5 is a Windows optional component that allows Windows 11 to run applications built for .NET Framework versions 1.0 through 3.5. It includes .NET Framework 2.0 and 3.0 — which is why older applications may request “.NET 3.5” even when they were built for an earlier framework version. The single .NET Framework 3.5 component satisfies all three older version requirements.

Windows 11 does not have a separate feature called “.NET Framework 2.0.” To support applications built for .NET Framework 2.0 or 3.0, enable .NET Framework 3.5 (includes .NET 2.0 and 3.0). Installing .NET Framework 4.x alone will not satisfy an application that specifically requires .NET Framework 2.0, 3.0, or 3.5.

Common applications that require .NET Framework 3.5 include older accounting software, engineering and CAD tools built between 2007 and 2014, legacy database management tools, older HP and Dell diagnostic utilities, some older installer packages, and many games from the mid-2000s to early 2010s.

This is completely separate from modern .NET runtimes like .NET 8.0 or .NET 9.0 — those are cross-platform runtimes installed independently for modern applications. .NET Framework 3.5 is specifically the legacy Windows-only runtime for older software.

Method 1 — Windows Features (GUI — Easiest Method)

This is the simplest method and works on Windows 11 versions 25H2 and earlier. It requires an internet connection — Windows downloads the necessary files from Windows Update during the process.

Step 1 — Open Windows Features

Press Win + R to open the Run dialog. Type optionalfeatures and press Enter.

The “Turn Windows features on or off” dialog opens.

Alternatively: open Start, search for “Windows Features,” and select “Turn Windows features on or off” from the results.

Step 2 — Find .NET Framework 3.5

In the Windows Features dialog, scroll down to find .NET Framework 3.5 (includes .NET 2.0 and 3.0). It appears near the top of the list.

Step 3 — Enable the feature

Check the checkbox next to .NET Framework 3.5 (includes .NET 2.0 and 3.0).

You do not need to expand the checkbox or select the child items — Windows Communication Foundation (WCF) HTTP Activation and Windows Communication Foundation (WCF) Non-HTTP Activation — unless you are a developer or server administrator who specifically requires those components.

Step 4 — Click OK

Click OK. Windows searches for required files and then connects to Windows Update to download them. A progress bar appears during the download and installation.

Step 5 — Restart if prompted

After the installation completes, Windows may prompt you to restart. If prompted, restart your PC. After restarting, .NET Framework 3.5 is enabled and any application requiring it should run.

Method 2 — DISM Command (Online — Fast and Reliable)

For users who prefer the command line, DISM installs .NET Framework 3.5 in one command. This method also requires an internet connection — DISM downloads the necessary files from Windows Update.

Open Command Prompt as administrator — right-click Start and select Terminal (Admin) or Command Prompt (Admin).

Run this command:

cmd

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All

DISM contacts Windows Update, downloads the .NET Framework 3.5 payload, and installs it. The process typically takes two to five minutes depending on your connection speed.

When DISM reports “The operation completed successfully,” restart your PC if prompted.

PowerShell alternative — same result:

Open PowerShell as administrator and run:

powershell

Enable-WindowsOptionalFeature -Online -FeatureName "NetFx3" -All

This produces the identical result as the DISM command — either works.

Method 3 — DISM With ISO Source (Offline — For Restricted Environments)

This method works when the PC has no internet connection, is restricted from accessing Windows Update, or when Method 2 fails with error 0x800f081f or 0x800f0906.

Do not install the regular .NET Framework 3.5 SP1 installer intended for older versions of Windows — on Windows 11, the supported offline method uses the matching Windows installation media or Features on Demand files.

Step 1 — Download the matching Windows 11 ISO

Download the Windows 11 ISO from Microsoft’s official software download page. The ISO must match your exact Windows 11 version, edition, language, and architecture. Using a mismatched ISO is the most common reason this method fails.

Step 2 — Mount the ISO

Double-click the downloaded ISO file in File Explorer. Windows mounts it as a virtual drive and assigns a drive letter — for example, D:.

Step 3 — Run DISM with the ISO source

Open Command Prompt as administrator. Replace D: with your actual mounted ISO drive letter:

cmd

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /Source:D:\sources\sxs /LimitAccess

The /Source:D:\sources\sxs parameter points DISM to the sxs folder inside the ISO, which contains the .NET Framework 3.5 installation files. The /LimitAccess flag prevents DISM from attempting to reach Windows Update — it uses only the ISO source.

Step 4 — Verify and restart

When DISM reports completion, restart if prompted.

Using a temp folder instead of mounted ISO:

If you prefer to copy the sxs folder rather than keep the ISO mounted:

cmd

md C:\Temp

Copy the sxs folder from the ISO’s sources directory to C:\Temp. Then run:

cmd

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /Source:C:\Temp\sxs /LimitAccess

Method 4 — Control Panel (Alternative GUI Path)

An alternative GUI path for users who prefer Control Panel over the Run dialog.

Open Control Panel. Go to Programs. Click “Turn Windows features on or off.” This opens the same Windows Features dialog as Method 1. Check .NET Framework 3.5 (includes .NET 2.0 and 3.0), click OK, and allow Windows to download and install the component.

Method 5 — Standalone Installer (Windows 11 26H1 Build 28000 and Later Only)

Starting with Windows 11 26H1 (build 28000 and later), .NET Framework 3.5 is only available as a standalone installer. Windows Features and DISM cannot install it on these releases.

Go to Microsoft’s official .NET Framework 3.5 download page: dotnet.microsoft.com/en-us/download/dotnet-framework/net35-sp1

Download the .NET Framework 3.5 SP1 standalone installer for Windows 11 26H1. Run the downloaded installer as administrator. Follow the installation prompts. Restart when prompted.

Confirm the computer is running Windows 11 26H1 (build 28000) or later at Settings, System, About before using this method — the standalone installer is specific to these newer builds.

How to Verify .NET Framework 3.5 Is Enabled

After installation, confirm .NET Framework 3.5 is active before testing your application.

Method A — Windows Features

Open Windows Features (Win + R, optionalfeatures). The checkbox next to .NET Framework 3.5 (includes .NET 2.0 and 3.0) should be filled — a solid checkmark indicates full installation.

Method B — DISM Query

Open Command Prompt as administrator and run:

cmd

DISM /Online /Get-FeatureInfo /FeatureName:NetFx3

Look for “State: Enabled” in the output. If it shows “State: Disabled,” the installation did not complete successfully.

Method C — PowerShell

Open PowerShell and run:

powershell

Get-WindowsOptionalFeature -Online -FeatureName "NetFx3"

A State of “Enabled” confirms successful installation.

Common Errors and How to Fix Them

Error 0x800f081f — Source Files Could Not Be Found

This is the most common error when enabling .NET Framework 3.5 on Windows 11. It means DISM tried to download the installation files from Windows Update but could not access them — either due to no internet connection, a firewall restriction, or WSUS blocking the request.

Fix: Use Method 3 — DISM with ISO source. Download the matching Windows 11 ISO, mount it, and point DISM at the sxs folder with /LimitAccess.

If you are seeing this error specifically while troubleshooting a Windows Update failure, our guide on error 0x800f081f covers the broader context and additional fixes.

Error 0x800f0906 — Files Could Not Be Downloaded

Similar to 0x800f081f but specifically indicates that DISM attempted and failed to download from Windows Update. Common on systems behind corporate firewalls, WSUS environments without the necessary .NET 3.5 payload, or systems with no internet access.

Fix: Use Method 3 with the ISO source. If WSUS is the issue, the IT administrator needs to add the .NET Framework 3.5 payload to WSUS or enable direct Windows Update access for .NET feature installation.

Error 0x80070643 — Installation Failure

If the installation fails with 0x80070643 after apparently completing the download, a system file issue is preventing the component from registering correctly.

Fix: Run SFC and DISM repair first:

cmd

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

Restart after both complete, then retry enabling .NET Framework 3.5. Our guide on error 0x80070643 covers this error in full detail.

“Windows Couldn’t Complete the Requested Changes”

This generic Windows Features error during .NET 3.5 installation indicates the online download failed.

Fix: Try Method 3 with the ISO source. If that also fails, run DISM /RestoreHealth first to repair the component store, then retry.

“Download Files From Windows Update” Prompt With No Internet

When Windows Features finds no local source for .NET 3.5 and prompts you to download from Windows Update, but the PC has no internet access, the installation stops.

Fix: Click “Skip this download” to dismiss the prompt, then use Method 3 with the ISO source to install offline.

Application Still Says .NET 3.5 Is Missing After Installation

If you have confirmed .NET Framework 3.5 is enabled via DISM query but the application still reports it as missing, restart your PC completely. Some applications check .NET status during startup and cache the result — a restart forces them to re-detect the newly installed framework.

If the application persists in reporting .NET 3.5 as missing after a restart, try running it as administrator. Some legacy applications check .NET status with elevated permissions and fail to detect it when run as a standard user.

Quick Comparison — Which Method to Use

Situation	Best Method
Windows 11 25H2 or earlier, internet available	Method 1 or Method 2
Windows 11 26H1 (build 28000+)	Method 5 — Standalone installer
No internet connection	Method 3 — DISM with ISO
Corporate WSUS environment	Method 3 — DISM with ISO
Method 2 failed with 0x800f081f	Method 3 — DISM with ISO
Prefer command line	Method 2 — DISM online
Prefer GUI	Method 1 — Windows Features

Enterprise Deployment — Group Policy and WSUS

For IT administrators deploying .NET Framework 3.5 across multiple Windows 11 machines, several additional options are available beyond the methods above.

Group Policy deployment:

Configure Group Policy to specify an alternate source for Windows features. Open Group Policy Editor, navigate to Computer Configuration, Administrative Templates, System, and find “Specify settings for optional component installation and component repair.” Enable this policy and set the alternate source path to a network share containing the sxs folder from a matching Windows 11 ISO.

WSUS with Features on Demand:

If your WSUS server includes Features on Demand packages, clients can download .NET Framework 3.5 through WSUS without requiring direct internet access. Verify that the .NET Framework 3.5 Features on Demand package is approved in WSUS for your target Windows 11 version.

DISM with network share:

Replace the local ISO path with a UNC path to a network share containing the sxs folder:

cmd

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /Source:\\ServerName\Share\sxs /LimitAccess

Task Sequence deployment (SCCM/Intune):

Add a DISM command step to your task sequence to enable .NET Framework 3.5 during OS deployment, pointing at the sxs folder from the deployment media.

Frequently Asked Questions