Just a follow-up:
I decided to contact Support because I figured it was their problem to fix.
Basically, they had me clean up Windows, remove all of the Message folders, rename the Corel directory to .old and overwrite it.
I run Disk Cleanup regularly so I know that wasn't the problem. Apparently, it was "remants" (I'll use that word to be polite) created by Corel.
At this point there are two Message.policy files (one for each of my two Corel products). Both have the default Value set to "opt-out".
I'll see if it sticks.
Perhaps it was partly my fault because I didn't want to make any changes to PSP configurations/Messages etc. when I installed it in April. I usually do that with new software so I can see how it performs on its own in the beginning. Everything was fine, coincidence or not, until the patches arrived.
I realize Alludo is a business and that revenue is important in order to keep the prices down and provide service. However, if the ads are inevitable with new installs, providing the customer with additional instructions up front, other than just a reset might free up the support staff a bit. If there is a FAQ for this I missed it. I still miss having a Jasc hardcopy manual in my lap as I work.
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Edit: I spoke too soon. As soon as I worked in PSP2023 today the message folder began filling. (Yes, I've unchecked them in the UI.) By the time there were about 6 messages in there my computer was as hot as a baked potato and slowing down. The only thing I can do is delete messages daily. What a pain! If anyone knows another solution, please let me know.