To reproduce:

DataTable dt = new DataTable();
dt.Columns.Add("Id", typeof(int));
dt.Columns.Add("Name", typeof(string));
dt.Rows.Add(1, new string('G', 32001));
this.radGridView1.DataSource = dt;
this.radGridView1.PrintPreview();


Workaround:  this.radGridView1.PrintCellFormatting+=radGridView1_PrintCellFormatting;

 private void radGridView1_PrintCellFormatting(object sender, PrintCellFormattingEventArgs e)
        {
            e.PrintCell.Text = e.PrintCell.Text.Substring(0,Math.Min(e.PrintCell.Text.Length, 32000));
        }