Clicking a folder in the New Outlook sidebar should instantly display its messages. When the client returns the error "Unable to find the folder" or "The folder cannot be found", the interface is attempting to query a folder identifier that no longer matches the server. Because New Outlook uses cloud-synchronized navigation items rather than static local paths, resolving this error requires cleaning up stale directory pointers or clearing local WebView2 state.
Fast Fix
If the error occurs on a folder in your Favorites, right-click it and select Remove from Favorites, then find the folder under your main account tree and re-add it. If the error affects a regular mailbox folder, sign in to Outlook on the web (OWA) to confirm the folder still exists on the server.
Diagnostic Snapshot
| Property | Details |
|---|---|
| Symptom | Clicking a sidebar folder or Favorite throws “Unable to find the folder” |
| Root Cause | Stale Folder ID in cloud navigation, broken delegation link, or corrupt IndexedDB cache |
| Common Scenarios | Renamed/moved folders, shared mailboxes, or recently migrated mailboxes |
| First Action | Remove and re-pin the folder shortcut from Favorites |
Why New Outlook Loses Folder Paths
In classic Outlook, folders were mapped to local entry identifiers stored inside an offline .ost database. In New Outlook, folders are accessed as live cloud objects through Microsoft Graph and modern Exchange Online protocols.
Each folder in your mailbox possesses an immutable server-side string called a Folder ID. New Outlook references these IDs across three layers:
User clicks Sidebar Item
│
├── 1. Reads pointer from Navigation Cache (Favorites / Account Tree)
│
├── 2. Sends request via Microsoft Graph to Exchange Online
│
└── 3. Server validates Folder ID & Permissions
├── Match Found ────> Folder contents display
└── Broken Pointer ──> ERROR: "Unable to find the folder"
The pointer breaks when:
- The Folder Was Altered Elsewhere: If you rename, move, or delete a folder using a smartphone or web browser, the shortcut pinned in New Outlook’s Favorites may continue pointing to the obsolete Folder ID.
- Delegate Access Lapsed: If the folder belongs to a shared mailbox or another user’s delegated account, changes in tenant permissions invalidate the client’s access token for that specific container.
- Local Shell Desynchronization: The Edge WebView2 runtime’s local storage retains an outdated folder hierarchy that does not match current Exchange Online metadata.
Progressive Troubleshooting Steps
Step 1: Remove and Re-Add the Shortcut (Favorites)
If the error occurs primarily when clicking items inside the Favorites section at the top of the sidebar:
- Right-click the problematic folder under Favorites.
- Select Remove from Favorites.
- Scroll down to your primary mailbox folder tree.
- Locate the actual folder in your mailbox hierarchy.
- Right-click the folder and select Add to Favorites.
This discards the stale cached shortcut and writes the correct, current Folder ID to your cloud profile. For more details on navigation issues, see:
Step 2: Validate Folder Existence in Outlook on the Web (OWA)
To determine whether the folder exists on the server or is entirely lost:
- Open a web browser and sign in to Outlook on the web (
outlook.office.com). - Look for the folder in the sidebar.
- If the folder is missing in OWA: The folder was moved, renamed, or deleted by a rule or another client. Check your Deleted Items folder to recover it.
- If the folder opens normally in OWA: The issue is isolated to your desktop client’s local cache. Proceed to Step 3.
Step 3: Clear the Local New Outlook App Cache
If OWA opens the folder without issue, force the New Outlook desktop shell to rebuild its local directory tree:
- Close New Outlook completely.
- Press
Ctrl + Shift + Escto open Task Manager and verify thatolk.exeis not running. - Press
Win + R, paste the following path, and press Enter:%localappdata%\Microsoft\Olk - Select all items inside the folder and delete them.
- Relaunch New Outlook. The app will pull a fresh folder manifest directly from Exchange Online.
Step 4: Reconnect Shared Mailbox Folders
If the error appears when opening a folder inside a secondary or shared mailbox:
- Right-click the shared mailbox name in the folder pane and select Remove shared folder.
- Close and restart New Outlook.
- Right-click your primary account heading (or Folders), select Add shared folder or mailbox, enter the email address again, and click Add.
Folder Pane > Primary Account
└── Right-click "Folders"
└── [ Add shared folder or mailbox ] <-- Re-links shared mailbox path
If the shared mailbox refuses to open or fails to load entirely, follow our dedicated resolution guide:
Hard Stops: Account Type Conflicts
If the missing folder belongs to a disconnected archive file (.pst) from a previous classic Outlook installation, New Outlook cannot mount it. New Outlook operates exclusively on cloud mailboxes:
If your organization requires managing local file-based folder structures or complex shared mailbox hierarchies that fail to resolve in the modern client: