I have a new Raspberry Pi 3 Model B. It has been working fine with the keyboard and mouse. I have ran rpi-update since purchasing it and it continued to work fine after that. I have tried starting the Raspberry Pi with the keyboard and mouse off with the wireless USB receivers plugged in. I have tried starting the Pi with the USB receivers out and then plugging them in. Neither results in the keyboard working. My Pi is setup to boot to the command line. I have also tried plugging the micro USB power adapater into a different outlet in my home. This still results in the thunderbolt icon appearing.
I am not sure what to do next to troubleshoot the problem. Should I just try to return it?
EDIT: Duplicate question w/ answer which I could not find before - RPi undervoltage