E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)

README.md

This may happen if:

• 'Synaptic Package Manager' or 'Software Updater' is open.
• Some apt command is running in Terminal.
• Some apt process is running in background.

For above wait for the process to complete. If this does not happen run in terminal:

sudo killall apt apt-get

If none of the above works, remove the lock files. Run in terminal:

sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock
sudo rm /var/lib/dpkg/lock*

then reconfigure the packages. Run in terminal:

sudo dpkg --configure -a

and

sudo apt update