Why unable create database if application install in C:\program files

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C

C#

if My Application Executable Path in C:\Program Files then Database Create Code not Work Without any error but If My Application Executable Path in D:\ My Code Work Fine

but in my workplace we have a software which Install in C:\ Program Files and when i delete database from C:\ and open application automatic Create Blank Database

than why i not able create database in C:\

What I have tried:

public static string datafilename = Path.GetDirectoryName(Application.ExecutablePath)+ @"\Data.accdb";

private void Form1_Load(object sender, EventArgs e)
{
CreateDataBase();
}

private void CreateDataBase()
{

if (!File.Exists(datafilename))
{
label1.Text = "DataBase not found";
var cat = new ADOX.Catalog();

cat.Create("Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source="+ datafilename + ";" + "Jet OLEDB:Engine Type=5");
label1.Text = "Database Created Successfully";
cat = null;
createTable();
}
else
{
label1.Text= "Database Found";

}
}