I am that person who use small SSD drive for Windows system and bigger, secondary HDD, for data. ICloud still do not allow you change destination folder for synchronization files with iCloud Drive. So i show you how to change folder, can be in another harddrive.
If you already have synchnonized iCloud Drive, you have to stop synchronisation between original folder. So open iCloud setting and uncheck synchronisation. After that turn disable all iCloud services in Task Manager.
By default, iCloud folder is linked to “C:\Users\\iCloudDrive”. You can check your username by open CMD and type “whoami”, result is computer name / username. We have to delete old (original) folder. Thats why we want to disable synchronization and stop services, becouse if you delete original folder while sync is active, iCloud will delete all files from iCloud drive.
If you follow my command, open CMD as admin and fill this code to setup destination folder in disk D:/ and folder iCloud:
mklink /J "C:\Users\Windows\iCloudDrive" "D:\iCloud"
After all, your iCloud drive will be located in disk D and folder iCloud.