Hi I have ASP .NET application. I set culture in Application_Begin request: System.Threading.Thread.CurrentThread.CurrentCulture = myCulture; System.Threading.Thread.CurrentThread.CurrentUICulture = myCulture; When I get current culture from page, it is myCulture in debug mode and it is "en-GB" in release mode. I don't understand why Release mode affects on Thread.CurrentThread.CurrentCulture I use VS2010 and .NET 4.0 Thanks