Unexpected error. Unable to install role: Web server (IIS) and all sub-options, during Application Suite installation on Windows 2012

Applies to: 

IAS 2014 and later on Windows Server 2012.

Blue's Enterprise 4 on Windows Server 2012.

Description:

During Application Suite installation on Windows Server 2012 one of the following errors can occur:

• Unexpected error. Unable to install role: Web server (IIS) and all sub-options
• Unable to install role: .NET Extensibilty 3.5. Try to install it manually using Server Manager

Cause:

Microsoft .NET 3.5 feature is not present on disk, Internet connection is not available, so it needs DVD installation disc

Solution:

1. Stop installation and exit
2. Open Server Manager
3. Press Add Role
4. Insert Windows Server 2012 DVD or mount iso to D drive. 
5. Open Add Roles and Features Wizard
6. Select Web Server (IIS) if not already installed.
7. Under Web Server (IIS), select .NET Framework 3.5 Features and then click next
8. Click next until Confirmation page 
9. Select 'Specify an alternate source path' link in the Confirm installation selections screen.
10. Insert/select path: D:\Sources\SxS\ and then click OK.
11. Click Install button to complete the setup, then you can re-install the Application Suite