Noob to arduino. Been in s/w development for far too many years.
elegoo uno r3 with the blink example. I did have a Adafruit 4485 Adafruit LSM6DS33 + LIS3MDL - 9 DoF IMU with Accel/Gyro/Mag - Stemma QT Qwiic working. Started to get LowLatencyDatalogger working. Compiled ok. I then plug in the Seeed SD Card Shield and noticed the println's were messed up. Regressed by removing the shield. No change. Went back to blink example. Still garbled println. Tried different USB cables/ different usb ports on my Chromebook. Even tried: Serial.wirte/print/println still garbled output. Tried different baud rates. Still garbled output.
delay(10); // will pause Zero, Leonardo, etc until serial console opens
// Serial.write("hello, world");
// Serial.print("hello, world");
output looks like
helhello, lo, worlworld
I did get a timeout twice while downloading the sketch. Good R3 gone bad?