For older versions of NET Framework, an installation on a Windows server must be performed in Server Manager. Please view the following instructions:
Enable .NET Framework 3.5 by using the Add Roles and Features Wizard
- In Server Manager, click Manage and then select Add Roles and Features to start the Add Roles and Features Wizard.
- On the Select installation type screen, select Role-based or feature-based installation.
- Select the target server.
- On the Select features screen, check the box next to .Net Framework 3.5 Features.
- On the Confirm installation selections screen, a warning will be displayed asking Do you need to specify an alternate source path?. If the target computer does not have access to Windows Update, click the Specify an alternate source path link to specify the path to the \sources\sxs folder on the installation media and then click OK. After you have specified the alternate source, or if the target computer has access to Windows Update, click the X next to the warning, and then click Install.
If you are using Server Manager in Windows Server 2012 to add a role or feature to a remote server, the remote server’s computer account (DOMAIN\ComputerName$) requires access to the alternate source file path because the deployment operation runs in the SYSTEM context on the target server.
If you need further assistance, please open a support ticket.