Outlook 2016 cached mode not updating
This also affected the ability to search public folders: because the items weren't cached, Outlook wasn't indexing the folder contents.Search only worked if you unchecked the Download shared folders option which switched the folders to online mode, where items were indexed by the server.This also made large public folders slow to use as the contents needs to sync down every time you switched to the folder.This issue was fixed in the in the January 3, 2017, update for Outlook 2016 (KB3141453) for MSI installations.
Changes like: EDIT: So for reference, it seems that clearing the offline items in the folder resolves the issue temporarily for everything accept the categories not updating.
The only work around for this is to uncheck the "download shared mailboxes" box, but we want to keep that checked to improve performance (when it is fully cached).
This seems like a widespread issue and I haven't seen any good answers besides unchecking the download box.
The email account that outlook is logged into appears to sync ok without needing to click Update Folders, it's only "shared" mailboxes.
Is there a setting that needs changing or is this how cached mode works. Please refer to this KB article for more information: https://support.microsoft.com/kb/3115602 There are a couple of different options you can take to resolve it depending on what works best for you.