Windows 11 now ships with the new Outlook app preinstalled, replacing the classic Outlook desktop client for many users. The new Outlook is a web-based version that does not support PST files, COM add-ins, or offline access to cached email. This article explains the key differences between the two versions and provides a step-by-step setup guide to make the new Outlook work more like the classic version you are used to.
Key Takeaways: Transitioning from Classic Outlook to New Outlook
- File > Options > General > Use the new Outlook toggle: Switch between new Outlook and classic Outlook at any time without reinstalling.
- Settings > General > Appearance: Change the layout to compact mode and set the reading pane to the right to match classic Outlook.
- Settings > Accounts > Sync: Configure which folders sync to your device to reduce online-only behavior and improve offline access.
How the New Outlook Differs from Classic Outlook
The new Outlook is built on Microsoft 365 web technologies. It uses the same server-side rules and security as Outlook on the web. This means the new Outlook does not download a local copy of your mailbox. Instead, it syncs data on demand when you are online. Classic Outlook uses a local OST file that stores a full copy of your mailbox for offline access. The new Outlook also lacks support for PST files, custom forms, and third-party add-ins that rely on COM architecture. All email processing happens on the server, which reduces local disk usage but requires a stable internet connection for many operations.
What Remains the Same
The new Outlook still supports Exchange Online, Microsoft 365 Groups, shared mailboxes, and public folders. Calendar sharing, scheduling assistant, and the focused inbox work the same way. Keyboard shortcuts like Ctrl+Shift+M for new mail and Ctrl+Shift+A for new appointment are preserved. The new Outlook also includes the same search experience powered by Microsoft Graph.
What Is Missing
Classic Outlook features that are not available in the new Outlook include: offline access to all cached email, PST file import and export, COM add-ins (such as CRM connectors or email signature tools), custom views and filters, VBA macros, and the ability to open other users’ mailboxes in a separate window. The new Outlook also does not support IMAP or POP accounts that are not hosted on Microsoft 365.
Best Setup Steps to Make New Outlook Feel Like Classic Outlook
You can configure the new Outlook to closely mimic the classic Outlook interface and behavior. These steps assume you have already launched the new Outlook app from the Start menu or taskbar.
- Switch to compact layout
Click the gear icon in the top-right corner to open Settings. Go to General > Appearance. Under Layout, select Compact. This reduces spacing between items and shows more messages on screen, similar to classic Outlook. - Set the reading pane to the right
In Settings > General > Appearance, find Reading pane. Choose Right. This matches the default reading pane position in classic Outlook. - Enable the classic ribbon
In Settings > General > Appearance, scroll to Ribbon. Select Classic ribbon. The new Outlook uses a simplified ribbon by default. Switching to classic ribbon restores the familiar tabs and commands from classic Outlook. - Turn off focused inbox
Go to Settings > Mail > Focused inbox. Toggle Sort messages into Focused and Other to Off. Classic Outlook uses focused inbox by default, but many users prefer a single inbox view. This setting moves all messages to the main inbox. - Configure sync settings for offline access
In Settings > Accounts > Sync, select your email account. Under Sync options, choose All folders. This forces the new Outlook to download all folders for offline access rather than syncing only recent items. Note that this increases local storage usage. - Set default reply behavior
Go to Settings > Mail > Compose and reply. Under Reply and forward, choose Include original message text. Classic Outlook includes the original message when replying. The new Outlook defaults to not including the original text. Change this to match your workflow. - Add shared mailboxes
In Settings > Accounts > Shared mailboxes, click Add shared mailbox. Enter the email address of the shared mailbox. The new Outlook supports shared mailboxes but requires you to add them explicitly rather than auto-mapping them like classic Outlook. - Set the default signature
Go to Settings > Mail > Signature. Create a new signature and set it as the default for new messages and replies. The new Outlook signatures are stored on the server and apply to all devices. Classic Outlook signatures are stored locally.
Common Issues and Limitations After Setup
New Outlook does not show all folders in the folder pane
The folder pane in new Outlook only shows folders that have been synced. To force all folders to appear, go to Settings > Accounts > Sync, select your account, and choose All folders. Wait a few minutes for the sync to complete. If folders still do not appear, remove the account and add it again.
Cannot open PST files or import data from classic Outlook
The new Outlook cannot read or import PST files. If you have archived email in PST files, you must keep classic Outlook installed to access them. You can also upload PST files to a Microsoft 365 mailbox using the classic Outlook import wizard, then access them in the new Outlook.
Keyboard shortcuts do not work the same way
The new Outlook uses a subset of classic Outlook shortcuts. Common shortcuts like Ctrl+Shift+M for new mail still work, but Ctrl+Shift+E for search folders does not. To see the full list of supported shortcuts, press Ctrl+Shift+? in the new Outlook. You cannot customize shortcuts in the new Outlook.
Third-party add-ins stop working
COM add-ins built for classic Outlook do not run in the new Outlook. The new Outlook only supports web add-ins built on the Office Add-ins platform. Check with your add-in vendor for a web add-in version. If no web version exists, you must continue using classic Outlook for that add-in.
Offline access is limited
The new Outlook caches recently accessed messages and attachments for offline viewing, but it does not download the full mailbox. If you lose internet connection, you can read only items that were already opened. To improve offline access, set sync to All folders and open each folder at least once while online to cache its contents.
New Outlook vs Classic Outlook: Key Differences
| Item | New Outlook | Classic Outlook |
|---|---|---|
| Mail storage | Server-side only | Local OST file with full offline copy |
| PST file support | Not supported | Full import, export, and archive |
| Add-in architecture | Web add-ins only | COM and web add-ins |
| Offline access | Limited to cached items | Full offline access to all synced data |
| Custom views | Not available | Customizable views and filters |
| VBA macros | Not supported | Full VBA macro support |
| Shared mailbox auto-mapping | Requires manual addition | Auto-mapped when permissions are granted |
| Keyboard shortcuts | Subset of classic shortcuts | Full customizable shortcut set |
After completing the setup steps above, you can navigate the new Outlook with the same layout and behavior as classic Outlook. If you need features that the new Outlook does not support, toggle back to classic Outlook by going to File > Options > General and turning off Use the new Outlook. For users who rely on PST files or COM add-ins, keep classic Outlook installed alongside the new Outlook. Test the new Outlook for a few days with your daily workflow before deciding to switch permanently.