I have a friend who is a member of a shared mailbox. The shared mailbox shows up in her Outlook but only displays emails going back 12 months. I had checked the settings of her own account and it was set to 12 months so I moved the slider to All, closed and re-opened Outlook but saw no sync activity. I waited a day but still no additional emails showed up even though there are emails going back a few years as proven by accessing it online.
BTW she is running Office version 1912 Build 12325.20344.
I decided to try adding the shared mailbox to her Outlook as a second account and was surprised to see it succeed although I didn't think you could add a shared mailbox that way.
I moved the slider for the account from 12 months to All and close/re-opened Outlook. Now older email started syncing into it.
So why won't email older than 12 months sync in when the mailbox is in Outlook without adding it as an account?
It should work in both ways you've configured it, but it might take a while for Outlook to reflect changes on existing profiles, depending on the size. And it's not that uncommon for the local OST file to get corrupted in some way. Creating a new profile is the usual approach.
@Cary Siemersthank you for the link. I forgot to say in my post that I had found that and tried it but while it changed the amount of offline mail for the user's own account, it didn't affect the shared mailbox as it's supposed to which surprised me.
@Vasil Michevcreating a new profile is one thing I didn't think of. However now that it's working for the person I don't want to mess with it. But if there is ever a need to remove the shared mailbox as an account, I will definitely try a new Outlook profile. Thanks for the reminder.