Create a new Outlook profile and set it as the default before reinstalling, because the migrated Outlook profile may be the part preventing Outlook from starting.
1. Create a fresh Outlook profile
This does not require Outlook itself to open:
- Quit all Microsoft 365 applications.
- Open Finder → Applications.
- Control-click Microsoft Outlook, then select Show Package Contents.
- Open Contents → SharedSupport → Outlook Profile Manager.
- Select Create a new profile (
+) and give it a name such as New Profile.
- Select the new profile, open the Set the default profile menu, and choose Set as Default.
- Start Outlook and add your email account. Outlook always opens its default profile. ^1^
Do not delete the migrated profile yet. A profile can contain locally stored messages, contacts, calendars, and settings. After Outlook opens and all expected mailbox content has synchronized, the old profile can be removed from Outlook Profile Manager if it is no longer needed.
2. If Outlook still does not open, remove and reinstall it
Since macOS will not let you move the app to the Bin, sign in with a Mac administrator account—or enter an administrator name and password when prompted. Microsoft’s Mac uninstall procedure requires administrator permission. ^2^
- Quit every Office application.
- Open Finder → Applications.
- Control-click Microsoft Outlook → Move to Bin.
- If Outlook appears in the Dock, control-click it and choose Options → Remove from Dock.
- Restart the Mac.
If Move to Bin remains unavailable, check whether Outlook is still running:
- Press Option+Command+Esc.
- Select Microsoft Outlook, if listed, and choose Force Quit.
- Return to Finder → Applications and try again using administrator credentials.
Then reinstall from Microsoft:
- Open
https://m365.cloud.microsoft/apps in Safari.
- Sign in with the Microsoft account associated with Microsoft 365 or Office.
- Select Install apps → Microsoft 365 apps.
- Open Finder → Downloads and double-click Microsoft Office installer.pkg.
- Complete installation, open Outlook, and sign in. ^3^
3. Only if a normal reinstall still fails
Remove Outlook’s migrated local container after making a backup:
- In Finder, press Command+Shift+G.
- Enter
~/Library/Containers and select Go.
- Copy the Microsoft Outlook folder to a safe location as a backup.
- Move the original Microsoft Outlook folder to the Bin.
- Restart the Mac and reinstall Outlook.
Warning: Removing Outlook container or profile folders can erase mailbox data stored only on the Mac. Microsoft specifically recommends backing up those folders first. Microsoft 365, Outlook.com, and Exchange mailbox data can normally synchronize again, but locally stored or POP data may not. ^2^ ^4^
References
- Manage profiles or identities in Outlook for Mac | Microsoft Support
- Uninstall Office for Mac | Microsoft Support
- Download, install, or reinstall Microsoft 365 or Office 2024 on a PC or Mac | Microsoft Support
- Go back to Office 2016 for Mac after upgrading to Office 2019 for Mac | Microsoft Support