unnessary serial output SD

My Teensy 3.6 is connected to a separate SD card reader. It reads text data. When I run this sketch on an Arduino UNO is runs fine. But on a Teensy 3.6 it won't start. When I start the serial monitor I get an empty serial message and the sketch starts running immediatly. This prevents using my Teensy 3.6 stand alone. Who kwows what I can do to use the Teensy stand alone? Thanks!

// Teensy 3.6 hangs on unnessary serial output on PC
//SD: 13=CK 12=DO 11=DI 4=CS
#include <SPI.h>
#include <SD.h>
#include <LiquidCrystal.h>
char inbyte;
const int chipSelect = 4;
LiquidCrystal lcd(9,8,6,5,3,2);
File myFile;
void setup() {
lcd.begin (20,4);
Serial.begin(9600);
while (!Serial) { ; }
lcd.print ("init SD card");delay(2000);
if (!SD.begin(chipSelect)) {
lcd.print ("init failed");delay(2000);
return; }
lcd.clear();lcd.print ("init done");delay(2000);
myFile = SD.open("test.txt",FILE_READ);
if (!myFile){lcd.print("error opening SD");delay(2000);}
else {
while (myFile.available()) {
inbyte = myFile.read();
lcd.print(inbyte);lcd.print(" ");delay(100); // show data
if (inbyte == '/'){break;} // end of data
}
lcd.print ("all done");
}
}
void loop()
{}
-----------

the line waits for serial terminal to be connected.
either remove line ans all Serial lines
or modify

also use to better format your code on forum (so we can read it better)

Thanks WMXZ. It works nice!

FYI - IIRC: Serial.begin(9600); was changed a build or so back to wait for some time over 1 second for serial to appear before it returns. This gives a short built in wait until connected. I don't find the code behind it though.