Possibly after a Windows Update, accessing the Mail Security for Microsoft Exchange administration console will result in a Microsoft .NET framework "Configuration system failed to initialize" error.
You can choose to Quit or to Continue, but the process hangs there and the administration console never comes up.
Outer Exception Type: System.Configuration.ConfigurationErrorsException
Outer Exception Message: Configuration system failed to initialize
Outer Exception Source: System.Configuration
---Outer Exception Stack Trace---
at System.Configuration.ClientConfigurationSystem.EnsureInit(String configKey)
at System.Configuration.ClientConfigurationSystem.PrepareClientConfigSystem(String sectionName)
at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String sectionName)
Corruption in .NET 3.5 framework. Specifically the host-specific machine.config file may be corrupted.
Repair the .NET 3.5 framework installation. It is not necessary to uninstall/reinstall, a repair installation of Microsoft .NET 3.5 will suffice.