macOS Catalina 10.15.4 update will not install
I have downloaded the latest update to go from 10.15.3 to 10.15.4. It downloaded as normal and then offered to 'Install Now' with computer restart. The restart involved the progress bar under the Apple logo, as expected (although probably too quick for an update). After the mac restarted, I log in only to find that the update has not installed and I am still on 10.15.3.
Anyone have any ideas or know where I could start with troubleshooting?
MacBook Air 13", macOS 10.15