Malware was recently discovered for macOS devices that allows an attacker to bypass Apple’s security requirements that are in place to protect you and your data. Apple has released an update to block this malware, and we may need to restart your computer to install this update.
You will see a prompt soon asking you to install this Critical Update. This prompt will allow you to either install the upgrade now or install it at your earliest convenience.
If you choose to be reminded later, then you will be given instructions on how to upgrade on your own schedule.
You will find an application in your Applications folder called Software Center. You will need to open it to find the update tool.
Then look for macOS Updates and click Check.
The macOS Software Update tool will then open and list any updates that are available for you to install. If there are any updates available, then go ahead and click Update/Restart Now.
IMPORTANT: This update is required!
If you do not install the critical updates before the deadline, you will receive one final warning after 1:30 a.m. on Thursday, May 6. This last warning will give you 30 minutes to save all your work before the patch is installed, and your computer is rebooted.
It is possible that your computer is behind enough on updates that it will need to restart more than once. If you receive another prompt to update, then follow the same steps that you did before.
Although we can update your computer for you, we strongly recommend that you update early. Updating early allows you to choose when the update happens so that you can do your work when you need to, and so that you know your data is saved before the update starts.
— May 3, 2021