SD works, but displays SD CS error

Hi fellows,

on my project I'm writing data to a sd card.

void logInfo2SD() {


if (!SD.begin(chipSelect))
		{
			lcd.clear();
			lcd.setCursor(0,0);
			lcd.print("SD CS error");
			delay(1000);
			lcd.clear();
		}
		
		
	myLog = SD.open("my.log", FILE_WRITE);
	
	if (myLog)
	{
		myLog.print(RTC.get());
		myLog.print("\t\t");
		myLog.print("Pos: \t\t");
		myLog.println(position);
		myLog.close();
	}
	else
	{
		lcd.clear();
		lcd.setCursor(0,0);
		lcd.print("can't write log");
		delay(noticeRecognitionTime);
		lcd.clear();
	}
}

I always get this 'SD CS error', but in the end I get the data from SD card on a serial dump, as well as I verified the data using a SD reader on my computer:

my.log:
1490592912		Pos: 		11
1490592918		Pos: 		11
1490592924		Pos: 		11

So I wonder why I'm always getting this error and how to avoid this.