Silly question about multiple users on MacOS

Hello all,

I’ve never really had to test/think about this – and figured I would check here.

When you log in to a different user on a Mac – what happens to any processes that are running for that first user? Are they terminated/suspended or paused? Or do they keep running in the background? Or is it dependent on the type of process (i.e system specific vs third-party)?

You can enable Fast User Switching and switch back and forth between accounts without terminating the open apps in the account you switched from.

How individual apps handle this … not sure of the technical answer. But, I’ve never noticed something amiss when I’ve fast-switched accounts. The apps that were open, the documents that were open, the browser pages that were open, the mail that was in the process of being composed – all of these remain intact for me when I switch back.


Processes keep running unless the app has some form of timeout.

If you run low on memory though, some of the memory will be pushed out of physical memory to swap files (memory on disk) this isn’t as big an Issue if you’re on SSD. This merely slows down your recovery to normal operation when you switch user back to the original and activate that program.


Yup. Unix doesn’t care if you have multiple users logged in at the same time.

Users can use the same apps, as all settings, etc are stored per-user.

Starting several versions of macOS ago, you can even have one person logged in and using the GUI and have another user connect via Screen Sharing and also use their own login GUI. The main limitation is the processor and RAM of the Mac you are sharing.