iCloud for Windows Corrupt Database

I am running Windows 10 on an HP Pavilion computer. For several months I have been getting the following error message:

I tried signing out and signing back in and it did not fix the problem. I tried reinstalling the iCloud for Windows software and it did not solve the problem. Apple Support was of no help at all. Finally, I found a solution in the Apple Forums which fixed it.

IMPORTANT: This procedure will delete all the existing iCloud photos off of your computer, so you must BACK THEM UP first.

So, first of all, VERY IMPORTANT, make a backup of C:\Users\YOUNAME\pictures\iCloud Photos (Your iCloud Photos may be in a different directory. To find out where they are, open iCloud for Windows, and click on the Options button to the right of "Photos." A screen will open showing you the location of your iCloud photos.)

This is VERY IMPORTANT. Make sure that all of your iCloud Photos are backed up into a DIFFERENT DIRECTORY, and preferably also onto an external drive. Do not follow the instructions below if you do not know how to backup your iCloud Photos. You can call Apple Support and they will explain to you how to back up your photos.

If you are SURE that your iCloud photos have been backed up, then you can do the following:

1. Sign out of iCloud for Windows
2. Go to this folder within your AppData folder (it's hidden) C:\Users\YOURNAME\AppData\Local\Apple Inc (This will delete everything from your computer but not on iCloud Drive. You will see a warning.)
3. Delete the folders: iCloudDrive, iCloudPhotoLibrary, and CloudKit.
4. Log back in.
5. When you click the little iCloud icon in the notification area on the far right of your task bar, and click "Download Photos". It will give you a choice to download "All Photos" or a specific year. Choose whichever one you want. This worked for me.

Once again, DO NOT DO THIS unless you are really sure that you know what you are doing and you are sure that you have backed up your iCloud photos properly. Get help from someone to backup your photos if you're not clear how to do it.