Raspberry Pi Problems and Fixes. Documented problems encountered with Raspberry Pi’s and how they were fixed.

Symptom

Pi would not boot. Get a screen saying.

You are in emergency mode. After logging in, type "journalct -xb" to view system logs, "systemctl reboot" to reboot, "systemctl default" or "exit"

Cannot open access to console, the root account is locked.
See sulogin(8) man page for more details.

Press Enter to continue.

Cause

USB drive was configured to automount in /etc/fstab.
The USB disk was removed a while ago. So this problem only surfaced after a reboot.

Solution

Commented out the line in /etc/fstab

sudo nano /etc/fstab

#/dev/sda /mnt/usb vfat defaults 0 0

No Sound Via HDMI

Solution

edit the config.txt file

sudo nano /boot/config.txt

hdmi_group=1
hdmi_mode=16
hdmi_drive=2