It happens every time I load the application. I have 4 different apps that I load on that machine and they all take a very long time to load compared to my development box. The server is a 2.4 GHz dual xeon processor machine running Windows Server 2003, which comes with .NET preinstalled. My dev box is a 2.4 GHz single processor laptop. I thought perhaps it was because I did not change tempuri.org in the XML file that the app has to load, because the server does not have access to the internet. However, if I delete the tempuri.ord entry I the app still loads slow. Robert

As usual you are a big help. I will looking thread pooling as a solution. Thanks, Robert

Well I did try following that example and it worked up to a point. I get Serialization exceptions because .NET is trying to serialize System.Threading.Thread and other System classes. I can only modify my own classes to meed serialization requirements. What do I do about the System classes I need objects of sever System types in the assembly that I am trying to load into a separate AppDomain. For more than 2 years I did not have any such issue because I was loading assemblies into the default AppDomain. But I now have a need to dynamically load and unload them. Do you know of a solutions that will not try to serialize System classes. I can only modify my classes with MarshalByRefObject or [Serializable]. Thanks Robert

Oops, that last part of the quote was actually supposed to be UInt32, but you're right - I obviously couldn't perform basic math that day. :-O Microsoft MVP, Visual C# My Articles

I was able to get it working with your help sir. Thank you very much.