Using Outlook for iOS for personal email and calendar management
This error usually means the sync protocols are not associated with Outlook, or Office needs repair. Follow these steps in order:
- In Windows, open Start > Settings > Apps > Default apps.
- Select Set defaults by app.
- Find Outlook, select it, then choose Manage.
- Check each file type and make sure it is associated with Outlook.
- Close that window.
- Repair Office:
- Open Start > Settings > Apps.
- Select the Microsoft Office product and choose Modify.
- If it is Click-to-Run, choose Online Repair > Repair.
- If it is MSI-based, choose Repair > Continue.
- Restart the PC and try the iCloud sync again.
If that does not fix it, check for older Office versions in Control Panel > Programs and Features and uninstall any older version found, then restart and test again.
If Office was installed from the Microsoft Store or came preinstalled as Microsoft Office Desktop Apps, uninstall that installation from Settings > Apps, restart, and then reinstall Office.
There is also a PowerShell-based reconfiguration path for the Microsoft Store Outlook installation. This requires administrator privileges and changes the installed app configuration, so use it carefully. After running those commands, Office still needs to be repaired.