The feature is still in development. Microsoft estimates February 2027 for general availability. Here's what the roadmap says, why people want this, and what you can and can't do until it ships.
What Microsoft Has Announced
According to the roadmap entry, Outlook will remember the expanded or collapsed state of folders and shared mailboxes across restarts. The goal is that you pick up where you left off instead of opening the same folder branches again.
| Roadmap field | Listed value |
|---|---|
| Roadmap ID | 579187 |
| Product | Outlook |
| Status | In development |
| Platforms | Desktop, Web |
| Release ring | General Availability |
| Cloud instance | Worldwide (Standard Multi-Tenant) |
| Estimated GA | February 2027 |
The entry is tagged #newoutlookforwindows, so this is about the new Outlook for Windows. Because "Web" is also listed, Outlook on the web is included too. It isn't a Windows-only change.
Summary: This is a planned change to how Outlook remembers the folder pane. It doesn't change your folders or messages. The target date is an estimate, not a promise.
Why People Wanted This
The demand is easy to see. On Microsoft's own Q&A forum, one user wrote that in classic Outlook "I always had certain folders expanded and if I closed Outlook and opened it again they would still be expanded. In the new Outlook all my folders are colapsed everytime I open Outlook."
The answer in that thread confirmed the gap: in the new Outlook for Windows, there currently isn't a feature that allows you to keep folders expanded between sessions. Each time you close and reopen Outlook, the folder structure resets to a collapsed state. The same reply called this a limitation of the new Outlook interface compared to the classic version, where you could maintain the expanded state of folders.
People with big folder trees put the problem most clearly. In another Microsoft Q&A thread, a user explained that "I like to keep certain folders expanded but not all. My only options now are to have all folders open (maybe 100?) or not have none open which does not work for me." If you have, say, a Clients folder with a subfolder per client and a year-by-year archive under each one, a collapsed tree on every launch means a dozen clicks before you can file your first email.
Others have asked about the reverse problem. As recently as July 2026, a Microsoft support moderator acknowledged that New Outlook does not have the same option as Classic Outlook to keep Inbox groups or categories collapsed by default. The only suggestion was to manually collapse the groups or folders after opening New Outlook. Roadmap item 579187 says Outlook will remember both expanded and collapsed states, so it should help both groups.
Summary: The new Outlook has reset the folder tree on every launch, while classic Outlook generally didn't. This roadmap item is meant to close that gap.
Shared Mailboxes Get Named for a Reason
Shared mailboxes are listed specifically in the roadmap entry, and that matters for admins and helpdesk teams. Shared mailboxes collapsing on startup is an old complaint that predates the new Outlook.
Back in 2021, an IT pro on Microsoft Q&A reported that a client's shared mailboxes get automatically collapsed on start up. They do not retain the last expanded view. The personal folder tree remembered its state; this only happens for Shared Mailboxes folders. An Exchange MVP answered that this was expected behavior. The work-around is to enable "Download Shared Folders" in cached Outlook mode and restart. Once those shared folders are cached, they should show up as expanded when you re-open Outlook.
That workaround applies to classic Outlook, which has a cached Exchange mode. It doesn't apply to the new Outlook, which is why shared mailboxes being named in item 579187 is welcome news for teams that handle support@, invoices@ or similar queues all day.
What You Can Do Right Now (Spoiler: Not Much)
Don't go looking for a hidden setting, because there isn't one yet. No toggle, policy or registry setting for this has been documented. Be suspicious of third-party "fix" pages that promise one; some of the guides floating around describe settings that don't exist in Microsoft's documentation.
Microsoft's Folder Pane support article for Outlook for Microsoft 365, Outlook 2024 and Outlook 2021 covers how to show, turn off or minimize the pane. In classic Outlook, that means View > Folder Pane > Off or Normal, plus a minimize control at the top of the pane. Those settings control whether you see the pane and how big it is. They don't save which folders are expanded, so they won't fix this.
In the meantime:
- Use Favorites. Pin the folders you use most to Favorites so you aren't digging through the tree every time.
- Classic Outlook users with shared mailboxes: check whether "Download Shared Folders" in cached mode applies to your setup. That's the community-reported workaround described above.
- Admins: keep an eye on the Microsoft 365 roadmap and Message Center for item 579187 changing from "In development" to "Rolling out." Microsoft says its roadmap dates are estimates and features can be postponed or cancelled.
Open Questions
The roadmap entry is short, and it leaves out a few things admins will want to know:
- Per device or synced? It doesn't say whether your folder state follows you between the desktop app and the web, or stays on each device.
- Changes to the tree: It doesn't say what happens when folders are renamed, moved or deleted, or when you add or remove a shared mailbox.
- Scope: No account types, licences, build numbers or rollout stages are given. The only cloud listed is Worldwide (Standard Multi-Tenant), so GCC and other sovereign-cloud customers shouldn't assume the same timing.
- Other session details: The entry only covers folder expansion state. It says nothing about remembering the selected message, scroll position or reading pane.
The Bigger Picture
This isn't a big feature, and that's partly the point. Most of the complaints about the new Outlook have been about small things classic Outlook did without anyone noticing, not missing headline features. One Q&A commenter wrote that "At some points is the new Outlook a step back for productive working in business." Remembering folder state is exactly that kind of thing.
If Microsoft wants classic Outlook users to switch willingly, it has to fix these gaps one by one, and this roadmap item is one of them. If it ships in February 2027 as planned, the new Outlook should remember your folder tree the way classic Outlook did. Until then, you'll have to keep expanding those folders by hand.
Summary: This is a useful, long-requested quality-of-life fix for the new Outlook for Windows and Outlook on the web, and shared mailboxes are explicitly included. It's in development with a February 2027 estimate, and there's no workaround yet for the new Outlook.