iCloud for Windows can't upgrade, uninstall, or repair. How can I proceed?
Try to remove manually all the file in:


c:\program files x86\common files\apple\internet services
or
c:\program files\common files\apple\internet services


Then, via https://discussions.apple.com/message/29281327#29281327 -


Press Win + R (the "Run" prompt should appear)
Type "regedit" (for the registry editor) &amp; press enter.
Make a registry backup first: press File > Export and save current state of registry
Find and delete all folders containing "icloud"


Finally, you should be able to restart the computer and download iCloud from the Apple Web Site

iCloud for Windows

Reinstall the program.