public List<string>  Test_IsDataLoaded()
    {
        try
        {
            if (GRIDTest.Rows.Count != 0)
            {
                int countvalue = GRIDTest.Rows.Count;
                GRIDTest.Rows[0].WaitForControlReady();

                List<string> ReleaseIDList = new List<string>();

                int nCellCount = GRIDTest.Cells.Count;

                for(int nCount = 0;nCount<nCellCount ;nCount++)
                  {
                        if(nCount %5==0)
                        ReleaseIDList.Add((GRIDTest.Cells[0].GetProperty("Value").ToString()));
                  }
                return ReleaseIDList;    
             }

        }
        catch (Exception)
    {
    }
}

Method throws me error = Not all code path return a value. Whats wrong in code.