private void WriteToLog(string source,string method,string msg)
{

 string LogFile =Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData) + "\\test";            
 LogFile = LogFile + "\\Log.txt";
 StreamWriter sw = new StreamWriter(LogFile,true );
 string str = DateTime.Now.ToString() + "source=" + source + "\t Method=" + method + "\t" + msg;
sw.WriteLine(str);
sw.Flush();
sw.Close();
}

上述代码在管理员帐户中完美运行,但在有限的用户帐户中失败