It is a very known problem and its been going on for a decade… There is countless threads maybe 100s on this problem with no solution and 1000 of votes on them apple ignores it and then the threads are being closed.
Only option in the long run is to resize you windows system partition to the size you need if possible …. an almost impossible task for a normal user.
I have tried moving the location of the entire microsoft picture folder to my data partition/drive. it seems to change destination path shown in the icloud windows app but the pictures still continue to download to windows/syste/user/etc.etc.
95% of windows pc have maybe 50-150gb available space on system partition so its a huge problem with the size of phone picture librarys today… so almost everyone will experiance windows giving you a “low diskspace” at some point because of this. There are also plenty other problems that might come up in future because of this.
Litterally 2 steps below in the settings of windows icloud app you can change the destination folder of shared album.. the button have simply been removed on icloud photos destination/sync folder so it may be a 30 second fix for apple.
Next problem is that icloud photos want to upload everything in your microsoft picture folder to icloud… no way to get around the option. so if you have 2tb photos in your windows picture library then they will be uploaded NO choice. Something many might realize too late.
I assume it is in hope you will need to buy even more icloud space since your picture libraries are now all mixed up on icloud photos and your phone. you can not choose a specific folder only.
I tried getting my pictures from iphone to my pc without icloud… 5 senior advisors could not help me. they all told me to go here and complain .. one even called me a conspiracy theorist… my problem is 400gb of pictures on iphone.
I will continue to find a solution and in the same time i will contact EU and Danish telecommunications appeal board.
will contact a danish public service tv program also and let them have a look.
I feel apple are keeping my pictures hostage