You Are Running Low On Memory warning on Air

Hello!

First, I'd run a malware scan with Malwarebytes for Mac:

Malwarebytes for Mac

Malwarebytes is a free utility, but it does offer a premium version for real-time protection.

Next, macOS Mojave is out-of-date. Your MacBook Air supports up to macOS Catalina, which is newer than Mojave.

You can upgrade here: How to download macOS - Apple Support.

Another thing I'd suggest is generating an EtreCheck report. EtreCheck is a simple, helpful utility to diagnose and identify both software and select hardware issues.

If your Mac is experiencing an issue, such as poor performance or running slowly, kernel panics, apps freezing or quitting unexpectedly, storage issues, and many more, generating an EtreCheck report is a great place to start for troubleshooting issues with your Mac while getting help at Apple Support Community. EtreCheck was developed by a highly respected member of these very Apple Support Community forums, and it is trusted by many users.

Downloading

To get started, download EtreCheck:

https://etrecheck.com/en/welcome.html

Click “download” on the site. The app will be downloaded to your Mac to your downloads location, which is the “Downloads” folder by default. This can be accessed by going to the Finder > Go (in the top menu bar) > Downloads.

Open the app, and generate a report

Open the downloaded application, and follow the initial steps to open the app. Choose a problem in the drop-down menu, and click Start. Creating a report typically takes 2-4 minutes on a healthy Mac.

View your report, and upload a copy to Apple Support Community

Once you have your report generated, you can upload it to Apple Support Community for us to review and provide suggestions. Please refer to this document with instructions for uploading your report and using the “Additional Text” function of Apple Support Community:

How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community

If you need help in the meantime, please let us know!

Jack

CareyMontana wrote:

My spouse does not understand the concept of malware/adware/scareware whatsoever? She keeps going to websites and clicking on popups unaware of the crap hiding behind these innocent little boxes?

As a result we are getting a dialogue box that pops up and overrides everything on the screen? It states that "Your Memory Is Full, Please close any open apps to free up space."

Read this: Phony "tech support" / "ransomware" popups and web pages - Apple Community. Install nothing in response to these scams. You need to do nothing except dismiss the page — and if you are unable to do that, follow that User Tip's instructions.

When I open the Activity Monitor I find that there is a process running called "_windowsserver."

That is a normal macOS process. It is responsible for drawing everything you see on a Mac's screen.