Write text files without Byte Order Mark (BOM)?

Try this:

Encoding outputEnc = new UTF8Encoding(false); // create encoding with no BOM
TextWriter file = new StreamWriter(filePath, false, outputEnc); // open file with encoding
// write data here
file.Close(); // save and close it

In order to omit the byte order mark (BOM), your stream must use an instance of UTF8Encoding other than System.Text.Encoding.UTF8 (which is configured to generate a BOM). There are two easy ways to do this:

1. Explicitly specifying a suitable encoding:

1. Call the UTF8Encoding constructor with False for the encoderShouldEmitUTF8Identifier parameter.

2. Pass the UTF8Encoding instance to the stream constructor.

' VB.NET:
Dim utf8WithoutBom As New System.Text.UTF8Encoding(False)
Using sink As New StreamWriter("Foobar.txt", False, utf8WithoutBom)
    sink.WriteLine("...")
End Using

// C#:
var utf8WithoutBom = new System.Text.UTF8Encoding(false);
using (var sink = new StreamWriter("Foobar.txt", false, utf8WithoutBom))
{
    sink.WriteLine("...");
}

2. Using the default encoding:

If you do not supply an Encoding to StreamWriter's constructor at all, StreamWriter will by default use an UTF8 encoding without BOM, so the following should work just as well:

' VB.NET:
Using sink As New StreamWriter("Foobar.txt")
    sink.WriteLine("...")
End Using

// C#:
using (var sink = new StreamWriter("Foobar.txt"))
{
    sink.WriteLine("...");
}

Finally, note that omitting the BOM is only permissible for UTF-8, not for UTF-16.

Just Simply use the method WriteAllText from System.IO.File.

Please check the sample from File.WriteAllText.

This method uses UTF-8 encoding without a Byte-Order Mark (BOM), so using the GetPreamble method will return an empty byte array. If it is necessary to include a UTF-8 identifier, such as a byte order mark, at the beginning of a file, use the WriteAllText(String, String, Encoding) method overload with UTF8 encoding.

Interesting note with respect to this: strangely, the static "CreateText()" method of the System.IO.File class creates UTF-8 files without BOM.

In general this the source of bugs, but in your case it could have been the simplest workaround :)