YCH Dev-Highly Reliable Offline Installation of .NET 3.5 on Windows 10 Intranets

Highly Reliable Offline Installation of .NET 3.5 on Windows 10 Intranets

Author: ych

### **Installing Microsoft .NET Framework 3.5 on Windows 10**

#### **Important Note:**
> During the installation of Microsoft .NET Framework, conflicts may occur with certain third-party antivirus or system optimization software, such as **Norton, McAfee, Avast, Kaspersky, Bitdefender**, etc. 
> It is recommended to install Microsoft .NET Framework before installing any third-party antivirus software. If you already have an antivirus program installed, please close or completely exit it before proceeding with the .NET Framework installation.

---

### **Checking Windows Version & Offline Installation**

1. Press `Win + R`, type `winver`, and press Enter to check your Windows version information.
2. Run the following command in an elevated Command Prompt (Run as Administrator):
   ```cmd
   dism.exe /online /enable-feature /featurename:netfx3 /Source:C:\YourWindowsVersionFolder\sxs
   ```
   *(Replace `YourWindowsVersionFolder` with the folder corresponding to your specific Windows version).*

Below are 6 offline .NET 3.5 package versions compiled from official Windows ISOs. After verifying their MD5 hashes, they can be categorized as follows:
* [1809](https://wws.lanzoui.com/i0zFtqaieoh "1809") (Can be installed standalone) — Password: `3quo`
* [1903, 1909](https://wws.lanzoui.com/igOZ5qaifmb "1903,1909") (Cross-compatible/can be mixed) — Password: `1ax1`
* [2004, 20H2, 21H1](https://wws.lanzoui.com/idDI6qaigsd "2004,20h2,21h1") (Cross-compatible/can be mixed) — Password: `9wr3`

---

#### **If the Installation Fails:**

The failure might be caused by Windows Update being disabled. To resolve this:
1. Press `Win + R`, type `services.msc`, and click **OK** to open the Services manager.
2. In the list, find **Windows Update** and **Background Intelligent Transfer Service** (BITS).
3. Double-click each service, click **Start** (if the button is grayed out, change the **Startup type** from "Disabled" to "Automatic" or "Manual" first, apply the changes, and then click **Start**).

*(Note: Once the .NET Framework installation is complete, you can stop and disable these services again if you prefer to keep Windows Update turned off).*

---

#### **Alternative Troubleshooting Step (CAB Package Installation)**

Type the following command in an elevated Command Prompt:
```cmd
dism.exe /online /add-package /packagepath:C:\microsoft-windows-netfx3-ondemand-package~31bf3856ad364e35~amd64~~.cab
```
*(Make sure to replace the path with the actual path where your `.cab` file is saved).*

After running the command, go to **Turn Windows features on or off** in the Control Panel, enable the **.NET Framework 3.5 (includes .NET 2.0 and 3.0)** option, and restart your computer if prompted (press `Y`).

---

#### **Resolving Software Conflicts**

If the installation still fails, it may be due to a conflict with active background processes. Open the **Task Manager** (`Ctrl + Shift + Esc`) and temporarily end any background processes related to third-party antivirus tools, firewalls, or other .NET Framework-related setup wizards.

---

### **Other Alternative Methods**

##### **Method 1: Official Standalone Installer**

You can download the official .Net Framework 3.5 SP1 offline installers (supporting both 32-bit and 64-bit systems) directly from Microsoft:

* [dotnetfx35.exe (Mirror 1)](https://download.microsoft.com/download/6/0/f/60fc5854-3cb8-4892-b6db-bd4f42510f28/dotnetfx35.exe "dotnetfx35.exe")
* [dotnetfx35.exe (Mirror 2)](https://download.microsoft.com/download/2/0/e/20e90413-712f-438c-988e-fdaa79a8ac3d/dotnetfx35.exe "dotnetfx35.exe")

##### **Method 2: Using NetFx3.cab**

1. Download the [NetFx3.cab](https://pan.baidu.com/s/1geAjsaf "NetFx3.cab") offline package.
2. Copy the downloaded `NetFx3.cab` file to the directory `C:\Windows`.
3. Open **Command Prompt** as an Administrator and execute the following command:
   ```cmd
   dism /online /Enable-Feature /FeatureName:NetFx3 /Source:"%windir%" /LimitAccess
   ```
   Wait for the deployment progress to reach 100%.

4. If this command fails, try running this alternative command instead:
   ```cmd
   dism /online /Enable-Feature /all /FeatureName:NetFx3 /Source:"%windir%" /LimitAccess
   ```

##### **Method 3: Clean CAB Installation Method**

Follow these steps in order:
1. Turn off or exit all third-party antivirus, security, and firewalls (e.g., Norton, McAfee, Avast, etc.).
2. Enable the **Windows Update** service in `services.msc`.
3. Go to **Turn Windows features on or off** and temporarily turn off **.NET Framework 4.6/4.8 Advanced Services** (or the corresponding higher version installed on your system).
4. Download the `NetFx3.cab` offline package and copy it to the `C:\Windows` folder.
5. Run **Command Prompt** as an Administrator.
6. Paste and run the following command:
   ```cmd
   dism.exe /online /add-package /packagepath:C:\WINDOWS\netfx3.cab
   ```
7. Once the progress bar reaches 100% and displays the package configuration and space release messages, the installation is complete.

Highly Reliable Offline Installation of .NET 3.5 on Windows 10 Intranets

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