> Source: [sk63803](https://support.checkpoint.com/results/sk/sk63803)

# sk63803 - E80 Endpoint Security Server .NET 3.5 installation on Windows 2008 Server R2 fails

| Property | Value |
|----------|-------|
| Solution ID | sk63803 |
| Date Created | 2011-06-21 |
| Last Modified | 2017-02-09 |
| Technical Level | General |
| Products | Endpoint Security |
| Versions | Cloud, E89.X, E88.X, R82.20, R82.10, R82, R81.20 |
| OS | Windows |

## Symptoms

- During E80 Server installation, this error appears: "You must use the Role Management Tool to install or configure Microsoft .NET Framework 3.5 SP1."

## Cause

Endpoint Security Management Server installation requires Microsoft .NET 3.5 SP1 Runtime Framework. On Windows 2008 Server R2 **only**, if it is not installed in advance, the installation will fail with the above error.

For any other Windows version, the Endpoint Server will install the Microsoft .NET as part of the installation process.

## Solution

Proceed as follows to install the Microsoft .NET 3.5 SP1 Runtime Framework prior to installation:

1. Open Server Manager (accessible by writing "Server Manager" in the Start menu search bar).

2. In the left pane, select Features.

3. In the right pane, click "Add Features". The Add Features Wizard dialog will be displayed.

4. In the wizard, expand ".NET Framework 3.5.1 Features" (found in the Features list).

5. Select ".NET Framework 3.5.1"

![Check the checkbox for .NET Framework 3.5.1](https://sc1.checkpoint.com/sc/SolutionsStatics/sk63803/Add_Features_Wizard.png)

6. Click "Next", and then "Install".

7. When the installation is finished, click "Close". There is no need to reboot.

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