I use MS Outlook 2016 on my PC for my email and also iCloud to synchronise my diary and contacts with my iPhone. Along came the latest Windows 10 Creator update and after installation I was unable to open my Outlook Calendar and People folders.
There are numerous suggestions on what do to do out there on the Internet some even suggesting all Apple software should be uninstalled and re-installed. I didn’t want to go to that extent, so instead just tried repairing my iCloud installation.
Firslty, make sure that Outlook is not running, then in Windows 10 select Settings, Apps & Features. Scroll down and click on the iCloud entry, then select Modify. Finally, select the Repair option and click on Next. Follow the dialog. Easy!