>To answer the test, when it freezes, I see that the Global.asax is able to get into Application_Start as it logs an entry. So, it freezes after that and before entering into my DLL.

Did you add any logging for Application_Error and Application_BeginRequest() ?

IAC, if the Application_End of the 'old' instance hasn't fired then it is still running and it may well be that it is preventing the new version from performing some action. For example does the application maintain exclusive use of some resource whilst it is running ?

Could you add a log entry to see it the process that is created in the initialization of the web form (which you mentioned in an earlier post) successfully ?