Created symlink from /etc/systemd/system/apt-daily.service to /dev/null. Created symlink from /etc/systemd/system/apt-daily-upgrade.service to /dev/null. Removed symlink /etc/systemd/system/timers.target.wants/apt-daily.timer. Removed symlink /etc/systemd/system/timers.target.wants/apt-daily-upgrade.timer. E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable) E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?