Solved: On lower spec systems (4GB RAM) the default swap file in /dev/dm-1 of 1GB is insufficient.
Addition of new swap file has resolved the stated issues. Filename Type Size Used Priority /swapfile file 4194300 2828 -2 /dev/dm-1 partition 999420 0 -3 digitalocean.com/community/tutorials/how-to-add-swap-space-on-ubuntu-18-04 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1798011 Title: HDD thrashing. System locks all input devices. Hard boot required to regain control. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1798011/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs