application memory

You get that message for 1 of 2 reasons.

1) Your boot drive is low on free storage, and macOS cannot create page and swap files so it can move modified virtual memory to storage. It needs to do this so it can free of memory for other apps to use.

I would suggest trying to keep between 50GB and 100GB of free storage, if you are going to be running larger memory hungry applications.

2) You a process or several processes that have asked for so much virtual memory that macOS can no longer create virtual memory page tables to keep track of all the virtual memory address requested. These page tables are kept in memory, so if enough of them are created, there is no memory left for the applications to run.

Applications -> Utilities -> Activity Monitor -> View (menu) -> All Processes -> Memory (tab)

can help you identify if any processes are consuming excessive amount of memory.

Keep in mind that if you have a web browser open with lots and lots of open tabs, each tab is run in its own process, however each of those processes will add up to using a lot of memory. so look at your browser usage.

Hi there sojourner129,

If you are seeing a message about memory usage on your Mac, this article has more information on how to use Activity Monitor in order to identify what app or process is responsible for this occurring and stop it: View memory usage in Activity Monitor on Mac

Let's also ensure your Mac is fully updated since this installs feature improvements and bug fixes that can resolve unexpected behavior like this. These steps from Update macOS on Mac walk you through how to back up and update:

Before following these steps, it's a good idea to back up your Mac.

1. From the Apple menu  in the corner of your screen, choose System Settings or System Preferences.

* If you chose System Settings, click General on the left side of the window. Then click Software Update on the right.

* If you chose System Preferences, click Software Update in the window.

2. Software Update then checks for new software. 

* If Software Update finds new software, click the button to install it. The button might be named Update Now, Upgrade Now, Install Now, or Restart Now, for example. You might then be asked to enter your administrator password.

* If Software Update says that your Mac is up to date, then no new software is currently available for your Mac model. Software Update shows only software that is compatible with your Mac.

Cheers!