So, came across a situation this week, where one org's users are creating hundreds of folders in the root of their Exchange Online mailboxes (not in the Inbox, but root).... We're having tons of issues with FSLogix and OST cache, having to reduce it to 1 month as of the end of this week. Craziest things I've ever seen with multiple users doing this (I think they were instructed by another user who is advising everyone they are an Outlook "Pro"). With all this being said, I'm assuming that under the default view, having hundreds of folders in the root causes all those to get cached in the framebuffer (for scrolling) since the mailbox is always expanded. I feel dumb asking this, but is this supported? Any consideration or comments you folks might have on this? I mentioned they should be using the Inbox, and creating subfolders (AR, AP, Clients) and organizing in there, instead of having all 3 combined in the base mailbox, but it sounds like it's getting shut down because there will be pushback from the Outlook "Pros"

honestly this is the first i've heard of any difference between where the folders live unless you're talking upwards of 10k of them, or a high number of synced public folders ... really more depends on amount of time synced - afaik outlook is going to cache the entire folder structure regardless of where it lives