WinForms Control hosted in IE - not always working

Question

I have a WinForms UserControl which I am hosting in IE (using tag). This was working on my development machine - most of the time. It's not loading now but it is loading fine on a remote machine pulling the control off the web server on my development machine. So I conclude that the DLL is in the correct place in the root directory of the website and the HTML is OK. Now As I investigate things get more confusing: - In the IIS webserver logfile it shows an http 200 result of serving the DLL - on the first request from my dev machine but it's a http 206 (partial data served) on subsequent reload requests from my dev machine. - It is not showing up in the GAC/download area (gacutil -ldl shows nothing) - Other UserControls which I haven't touched aren't loading I haven't during this time upgraded .NET or my system (as far as I can tell). Please help me!! I'm out of ideas on how to isolate the problem. Any solutions or suggetions welcome! Sincerely Buzzby.

Administrator · Answer

Check your security settings in IE and Code Access Security Policy in the .NET Configuration Settings. You need to give the zone Full Trust or just give the assembly full trust.