gistfile1.cs

class Program
{
    static int count = 100000;
    static int runningCount = 0;

    static void Main(string[] args)
    {
        var dict = new Dictionary<Guid, string>();
        var mre = new ManualResetEvent(false);

        for (int i = 0; i < 10; i++)
        {
            ThreadPool.QueueUserWorkItem((obj) =>
            {
                mre.WaitOne();

                while (true)
                {
                    try
                    {
                        var key = Guid.NewGuid();
                        dict[key] = "A"; // this line throws IndexOutOfRangeException
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine(ex.ToString());
                    }

                    if (Interlocked.Increment(ref runningCount) >= count)
                    {
                        Console.WriteLine("ThreadId: {0}  done!", Thread.CurrentThread.ManagedThreadId);
                        break;
                    }
                }
            });
        }

        Console.WriteLine("Press Enter to start");
        Console.Read();

        mre.Set();

        Console.WriteLine("starting");
        Console.ReadLine();
    }
}