Hi Faye,
>> On my public folder I can't select, property option, Total Number or total number of unread items checkbox (it's grayed)
Is this a problem that has only recently occurred?
I do conducted tests in my environment and found the same issue as you.

I did some search about this issue and found that it is by design and it is always the way it is has been. I'm afraid that we could not make changes to it.
For more information, please check: display number of unread items on public
folder.
Hope this can be helpful.
Regards,
Jeff Yang
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