Just FYI for anyone who might have clients running MYOB Payroll (and a few other MYOB products.
Seems they have not updated their product with newer code signing certs. They expired as of 1/05/2021 so all the various programs are popping up with warnings on load.
MYOB provides an option to "hide" the error for 90 days (interesting), but I have also just confirmed that at least two different AV products also check the digital sigs of files when loaded so while within the product it will do some odd ball things when the AV product denies access to the file due to the expired cert.
All of the above was news to the MYOB helpdesk this morning ....