iCloud für Windows does not install Add-In -> no sync

iCloud für Windows was installed on my Windows 11 Laptop and working fine

yesterday Outlook crashed, with the notification after restart that the Apple Add-In caused problems and has been deactivated

after checking, it turned out that the Add-In was not at the location Outlook was looking in

in fact, the search for aplzod showed that the add-in was not on the c-drive at all

uninstalled iCould for Windows and removed calendar remains from Outlook

re-installed iCloud for Windows - selected to sync Calendar and Contacts

the iCloud calendar shows in Outlook. HOWEVER no iCloud tab in the ribbon and the calendar does not sync

No reference to the iCloud Add in in the Outlook Add-In list and still no Add-in to be found on c-drive

it seems as if the iCloud for Windows installation has downloaded the calendar data and contacts alright but not installed the sync Add-In

(MS Office 2021 and Windows 11 are up-to-date)