You have a .NET Framework 2.0-based Multi-AppDomain application that uses objects. These objects have finalizers that start ThreadPool methods, for example, sockets. When you run the application, you notice that the CPU usage increases significantly.
This problem occurs because the finalizer invokes a ThreadPool method when an application domain is unloaded. Then, the data in the thread pool is corrupted and stops working for any other application domain.
981574 The splash screen stays open longer than usual when you try to start Excel on a computer that has the .NET Framework 3.5 SP1 installed
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.