To reproduce: use the following code snippet and click the button twice.

private DataTable GetTable01()
{
    DataTable table = new DataTable();
    table.Columns.Add("Dosage", typeof(int));
    table.Columns.Add("Drug", typeof(string));
    table.Columns.Add("Patient", typeof(string));
    table.Columns.Add("Date", typeof(DateTime));

    // Here we add five DataRows.
    table.Rows.Add(25, "Indocin", "David", DateTime.Now);
    table.Rows.Add(50, "Enebrel", "Sam", DateTime.Now);
    table.Rows.Add(10, "Hydralazine", "Christoff", DateTime.Now);
    table.Rows.Add(21, "Combivent", "Janet", DateTime.Now);
    table.Rows.Add(100, "Dilantin", "Melanie", DateTime.Now);

    return table;
}

private void button1_Click_1(object sender, EventArgs e)
{
    DataTable table01 = GetTable01();

    radGridView1.Rows.Clear(); 

    radGridView1.DataSource = table01;
}

WORKAROUND I:
this.radGridView1.DataError += radGridView1_DataError;

private void radGridView1_DataError(object sender, GridViewDataErrorEventArgs e)
{
    if (e.Exception is ArgumentException && e.Exception.Message == "Cannot clear this list.")
    {
        this.radGridView1.BeginUpdate();

        while (this.radGridView1.Rows.Count > 0)
        {
            this.radGridView1.Rows.RemoveAt(0);
        }

        this.radGridView1.EndUpdate();
    }
}

WORKAROUND II:
 while (this.radGridView1.Rows.Count > 0)
{               
     this.radGridView1.Rows.RemoveAt(this.radGridView1.Rows.Count - 1);
}