Hello Ewan,
We apologize for the inconvenience this has caused you.
Regrettably, there isn't a repair option available for AVG Antivirus for Mac.
We request you to reinstall your AVG Antivirus & check if the issue persists.
Refer to the below articles to perform the reinstallation:
- Uninstalling AVG Antivirus
- Reinstalling AVG Antivirus
Let us know if the issue still persists after the reinstallation.
We'll check & offer appropriate assistance.
Hello Midhun, thanks for your assistance. I have done as you suggested and uninstalled then reinstalled AVG Antivirus. However, the issue persists. 
If you have any further suggestions, I'll be happy to hear them.
Hello, I'm getting a message that Web Shield & Email Shield are not running, and that it is a problem on AVG side. This has persisted for about a week now. I see that there is a repair function in the Windows version, is there something similar in the Mac version that I can try, short of uninstalling and reinstalling?
Hello Ewan,
We apologize for the inconvenience this has caused you.
Regrettably, there isn't a repair option available for AVG Antivirus for Mac.
We request you to reinstall your AVG Antivirus & check if the issue persists.
Refer to the below articles to perform the reinstallation:
- Uninstalling AVG Antivirus
- Reinstalling AVG Antivirus
Let us know if the issue still persists after the reinstallation.
We'll check & offer appropriate assistance.
Appreciate your efforts in working towards fixing the issue, Ewan.
Please let us know the version of MAC & AVG (Open AVG program - Menu - About).
Also, the screenshot that you've shared in your previous post isn't accessible. Would you be so kind to share us the screenshot again, for better clarity?