Download all photos from iCloud to PC

Welcome to the Apple Support Communities!

I understand you are trying to synchronize your iCloud Photo Library with your PC. The resource below explains that once this is set up, new photos and videos will automatically download to your PC. You will need to download existing photos manually. I've highlighted some key information here for you. Click on the links for complete details.
Get help with iCloud Photos on your Windows PC

After you turn on iCloud Photo Library on all of your devices, any new photos and videos you add to your library will automatically download to your PC. You can also download your photos and videos by year.

Set up and use iCloud Photo Library on your Windows PC​

1. Download iCloud for Windows.
2. Open iCloud for Windows.
3. Next to Photos, click Options.
4. Select iCloud Photo Library.
5. Click Done, then click Apply.
6. Turn on iCloud Photo Library on all of your Apple devices.

Download your photos and videos from iCloud Photo Library

New photos and videos you add to iCloud Photo Library will automatically download to your PC. You can also download your collection by year when you follow these steps:

1. Open a File Explorer window.
2. Under Favorites, click iCloud Photos.
3. Click Download photos and videos.
4. Choose the photos and videos you want to download and click Download.

Your photos and videos download to the location you set in iCloud Photos Options.

Take care.

I did this, but it failed to copy the contents of year folders in iCloud to my PC - it simply copied an empty folder. Photos which were not in a year folder were copied successfully. I tried a couple more times but the same thing happened every time. What do I do next?

I have an empty download. Now what? thank you!

Also, Ive noticed that I have.... Photos, BackUp and WhatsApp and Im guessing its duplicating the same information, how can I know what its inside each folder? thank you!!