Heres a fantastic bit of ASPNET news from the A hrefhttpdiscussdevelopcomarchiveswaexeA2ind0211BampLDOTNET
Here's a fantastic bit of ASP.NET news from the DOTNET-CLR list...this bug has personally bit me a few times:
We are in the process of creating a hotfix for the "slow modem copy" issue described below. The hotfix has two new config settings: <httpRuntime waitChangeNotification="0" maxWaitChangeNotification="0" /> [...snip...] A production server under load will have a constant stream of incoming requests. Without the fix, a content update like the one described above might result in several AppDomain unloads/loads. It's also possible for sharing violations to occur, which would be seen as an error such as "Cannot access file 'AssemblyName' because it is being used by another process". It's easy to imagine a situation where ASP.NET is trying to load an assembly that is currently being copied into the bin folder. [...snip...] The fix is not yet available. I expect the KB article will be relased around the first week of December, at which point you can request the fix at no charge.