Content Studio does not work on .NET Framework 4.5 - Windows 8 / Server 8

Applies to:

• Content Studio 5.1, 5.2, 5.3 running on system using .NET Framework 4.5 (e.g. Server 2008 / Windows 8)

After installing Content Studio or after upgrading a computer running Content Studio with .NET Framework 4.5, you cannot connect to CS Admin since the web site crashes with the error
System.ArgumentException: Object of type 'System.Int32' cannot be converted to type 'System.Web.Security.Cryptography.Purpose'

.NET Framework 4.5 has changed internally in a way so that the Content Studio Cookie Encryption Module, used to encrypt the user's sessionId, no longer works. Since .NET Framework 4.5 is an in-place update of .NET Framework 4.0 everyone using or upgrading to this version will experience this problem. In Windows 8 / Server 8 .NET Framework 4.5 is installed by default.

Status

This problem only affects computer running a Content Studio Web site, clients or visitors are not affected.

Developers running Content Studio VSI might or might not be affected by this problem.

Uninstall .NET Framework 4.5 and then reinstall .NET Framework 4.0 including all released updates. Computers running a Content Studio Website version < 5.4 should not be upgraded to .NET Framework 4.5.

This problem will be fixed in Content Studio version 5.4.