When performing a one step update in Quicken 2018, you will always see a program updater window appear. This signifies that Quicken is attempting to perform an update behind the scenes. This happens in Windows, but on Windows directly, the update window is hidden from view. With Crossover, the update window is displayed.
Updater will run between 2-3 times: prior to the main window of financial institutions is displayed, once in the middle of that process, and once at the very end, after all the updates seem to be complete, but prior to the final completion status window is displayed (if you have the connection status window configured to display by default).
This repeated use of the Quicken Updater will extend the time it takes to perform a One Step Update. As such, please leave plenty of time for the update to complete before getting worried that Quicken has crashed. I will attempt to attach a video or screenshot of what this looks like to this tip.