This article covers how to protect your Mac with Sophos Home after installing or upgrading macOS 12, Monterey (released on October 25th 2021).
Sophos Home version 10.2.2 or higher is required to protect macOS 12 systems. See release notes:
Mac 10.2.2 – October 21, 2021
Installation videos
The installation process involves 4 steps – Refer to the step-by-step guide for additional details.
Step-by-step guide
The installation/upgrade process involves 4 steps:
Enabling System Extension
As the update/installation progresses, pop-up notifications will inform you if any extensions need to be Allowed via Security & Privacy.
There are 2 extensions involved: SophosWebNetworkExtension and SophosScanD.
You can need to check Security and Privacy to ensure there is nothing pending to be allowed:
Apple menu 
You are looking for this: (click on the images to see them in full size)
Allowing Notifications
A message will appear on the top right, informing users to enable notifications. Click on the message and use the slider to turn them on. You may need to perform this twice
Granting Full Disk Access to components
A Welcome to Sophos window will instruct the user to drag-drop extensions into Full Disk Access.
(click on any image to enlarge it in a new tab)
1 – Click on “Let’s Start” on the popup message
2 – Follow the instructions to open Security & Privacy (by clicking on “Click Here”)
3 – At the “Privacy” section, Scroll down to “Full Disk Access”, click on the padlock at the bottom left and enter your Mac’s username/password to allow changes, then drag and drop the “Drag this” image into the Security & Privacy window.
4 – Once you have dragged the Drag This image into the Security & Privacy. Several Sophos components will be added to the Full Disk access. Click Done and Close Security & Privacy
Note: If the steps are not completed the first time, the pop up will show up on reboot, and also whenever a scan has to take place.
Rebooting the Mac
Once finished following all the steps, restart your Mac to complete the installation process.
Known Issues
“This device is vulnerable”
The computer needs to be restarted to complete the installation. If the system is still vulnerable after a reboot follow the Troubleshooting section.
PrivGuard does not detect camera being in use on M1 Chips
Due to the new native camera detection functionality introduced in macOS 12, Monterey, Privacy Guard may not detect the camera being used for customers running M1 Silicon chips – Our dev team is looking at the problem for possible solutions.
Network Filtering applications interference
Network filtering applications such as Little Snitch or VPN software running in tandem with Sophos Home or other software with network filtering capabilities, may trigger errors or not work at all. If you experience issues with Sophos Home or another network based program, we recommend either disabling or removing the other program and re-testing functionality.