MailNow! 5 can be installed on Windows 8 and Windows Server 2012, however it requires .Net Framework version 2.0. User need to install and enable .Net Framework version 2.0 by following this guide below.
This document explains on how to enable and install .NET Framework 3.5 and change IIS .NET Framework version to 2.0 to be able to run MailNow! 5 on Windows Server 2012.
1. Install .NET Framework version 3.5
1.1. On the Windows Server 2012 desktop click the Server Manager button.
1.2. Click on the "Manage" button, then click on "Add Roles and Features" options.
1.3. Click on the "Next >" button.
1.4. Make sure the "Role-based or feature-based installation" option is chosen and click the "Next >" button.
1.5. From the "Roles" select the "Web Server (IIS)". A window will popup.
1.6. From the popup window choose "Add Features".
1.7. Expand the ".NET Framework 3.5 Features", select ".NET Framework 3.5 (includes .NET 2.0 and 3.0)" and click "Next >" button.
1.8. Continue on "Role Services" window, scroll down and choose "Management Tools", and make sure under "IIS 6 Management Compatibility" the "IIS 6 Scripting Tools" is selected"
1.9. Finally click on the "Install" button. Installation will take a few minutes.
2. Changing IIS to use .NET Framework version 2.0
2.1. This is an error page that you will face when IIS is on the default .NET Framework 4.0 when you try to access MailNow! 5.
2.2. From the Server Manager, click on "Tools" and select "Internet Information Services (IIS) Manager".
2.3. From the IIS Manager, click on "Application Pool", then click on "DefaultAppPool" and click the "Advanced Settings".
2.4. From the "General" section click on .NET Framework Version and change its value from v4.0 to v2.0 and click the "OK" button.
2.5. On the main IIS Manager window click on your machine name, then from the "Actions" click on "Restart". After restart is complete, you will be able to use MailNow! 5.