I was trying to install firefox from deb instead of firefox snap because the firefox extensions will not work in the snap version, but the system tried to re-install snap version instead. The dialog box asking to approve re-installing snap version closed without an answer and now apt is locked and cannot be unlocked.
Could not get lock /var/cache/apt/archives/lock. It is held by process 33889 (apt)
N: Be aware that removing the lock file is not a solution and may break your system.
E: Unable to lock directory /var/cache/apt/archives/
I have tried killing process 33889 but it will not die! The lock file in /var/cache/apt/archives/ appears to have 0 bytes.