My solution that worked for me.
- If you have any previous MS office ISO, install that over the existing installation
here, "previous" doesn't mean 2007 or 2013 or 2016, it could be the same version as you have currently installed that is showing the warning, just that the ISO was before that warning code was added to iso. I have a three year old ISO of MS office 2019, so I reinstalled that.
(note: no read to uninstall anything, as uninstalling will probably remove all settings you have changed in it)
2, disconnect net. (or you can even disonnect it before step 1)
- Run any office app (e.g. word or excel)
go to File - Account - Office Updates - select "disable updates"
close that app.
you can connect to net now.
Now, your office will not be updated so that culprit piece of code that started showing that "warning" will not come to your installation, and your office will run. However, you are stuck with the version of MS office that your ISO had. It will not get updated ever.
or you can search net and find the MS Office iso that was last just before that "warning", and then you can install that, and do the above and you will have MS office without that warning.
Thanks.