One way is to provide a redirect in the global.asax file:
void Application_Error(object sender, EventArgs e)
{
//uncomment this to narrow down 'helpful' microsoft messages
//HttpRequest request = ((HttpApplication)sender).Context.Request;
Exception ex = Server.GetLastError();
//ErrorManager is a custom error handling module
ErrorManager.ProcessError(ex);
Response.Redirect("~/error.aspx?error=" + HttpUtility.UrlEncode(ex.Message), true);
}
{ On a side note, I was getting an exception that I just couldn't track down - it just said 'file not found' but didn't say which file was missing. It turned out to be a broken image reference in a css file - breaking on line two of the code above helped identify the missing file }