iCloud for Windows did not install properly. To repair it, you need to go to Apps and features, select iCloud Outlook from the app list and click Modify. When prompted, click on Repair.

If your upgrade to iCloud for Windows has failed, check if your system meets the minimum requirements. Additionally, update the C++ Redistributable runtime files and disable Windows Defender Firewall.

The new version sports a friendlier look and layout, adds support for physical security keys, and fixes syncing glitches with Microsoft Outlook.