Chris_C1, iTunes does interact with Outlook, and that is what I need to know the inner workings of.
A search in MS OL link provided above was less than useless, as expected.
resulting in "Sorry, there are no results for _ModCal"
I really need to find a techie who knows iTunes on a pc, not the Microsoft Store version of iTunes (yes they are different).
These _ModCal entries are some kind of old bones.
Unfortunately, I cannot figure out where the dog buried them.
I'm guessing, that when iTunes syncs with Outlook, iTunes creates a changes file (_ModCalxxx)
and then merges the change file with the active Outlook.pst file.
Then deletes the _ModCal file.
No secret that iTunes updates have not always played well with Outlook,
and this, I believe, is a leftover from that interaction.
_ModCalxxx are not “real” calendars. They only show up in iTunes info section.
Not in Outlook calendars, and not on the iphone either.
No Outlook google connection at all. Not even Gmail.
No iCloud Outlook connection.
POP email connections.
Only Outlook.pst and archive.pst data files.
Thinking the _ModCal ‘s are stuck in some config file that I cannot find.
Even a windows registry search comes up nada.