P: Folder Favorite Setting Cannot Be Changed

Why conversations get merged: 

https://feedback.photoshop.com/conversations/lightroom-classic/lightroom-auto-import-to-folders-organized-by-date/5f5f44f14b561a3d422ab0ba?commentId=5f5f48984b561a3d422bdf45 

Right, unmarking favorite folders  and collections is very confusing, though working "as designed" -- it's a poor design. Please add your vote to this feature request to improve the usability:

https://feedback.photoshop.com/conversations/lightroom-classic/lightroom-lessconfusing-unmark-favorites/5f5f462a4b561a3d42776bff 

This thread is being merged into an authoritative thread for better tracking and response. 

I just submitted this feature request suggesting a simple way of eliminating the confusion over Unmark Favorites when a folder belongs to a favorites group containing multiple folders:
https://feedback.photoshop.com/photoshop_family/topics/lightroom-less-confusing-unmark-favorites

I just submitted this feature request suggesting a simple way of eliminating the confusion over Unmark Favorites when a folder belongs to a favorites group containing multiple folders:
https://feedback.photoshop.com/photoshop_family/topics/lightroom-less-confusing-unmark-favorites

You have proven to be a better software engineer than anyone at Adobe.  Congratulations!

I've had several folders stuck as favorites for over a year and I had about given up until I saw the new activity on this post. I had no idea about the favorite "groups" previously and did find a few that I was able to clear using the filmstrip shortcut but it did not solve my issue. I've tried every suggestion and literally everything possible in the program to remove them. I know my way around SQL so I decided it was time for me to fix this once and for all. Hopefully, a developer notices and can implement a way to resolve this "undocumented feature" for good.

Since I had so few favorites it was no big deal for me to wipe them all out and re-create later so I didn't bother implementing any restrictions to my delete statements. I did back up my catalog before the next steps.

First I exported the main lrcat as insert statements and searched for "fav" and found several hits but the only ones that I could validate were meaningful were AgLibraryFolderFavorite and AgLibraryOzFavoriteIds. These tables did indeed contain the favorite folders that I could not remove within the program. Deleted from those tables, wrote my changes but on opening Lightroom, 2 bugged out folders were STILL there!

I did some more digging and found helper.db in the Helper directory and discovered that the AgFolderSearchFTS_content directory also contained references to the favorite folders. I confirmed that the records were simply duplicated with an entry in column c6. So I deleted where c6 is not null, wrote my changes and said a prayer.

Opened Lightroom and finally, they are gone. This has been an incredibly frustrating bug that I am so relieved to have solved. Lightroom developers - please take note and help out the community, it shouldn't be an arduous task. I'm not going to spell out the steps as I do not want someone who does not know what they are doing destroying their catalog.

Besides the right-click bug, the confusing information you've observed is consistent with the (confusing) as-designed behavior of favorite groups (which I detailed above).  Let's walk through your description step by step:

[1] "assuming you have selected folder A and now right-click another folder B and mark it as a favorite, both folders A and B get the favorite star."

That's the bug for which I filed a separate bug report.  Two favorite groups are created, as indicated in the filmstrip's source-indicator pop-up: Folder: A, B and Folder: B. 

[2] "If you right-click A in the Folders panel, the Mark Favorite command is available while the folder is already marked as favorite with the star."

Folder A's icon in the Folders panel is marked with a star because A is contained in an existing favorite group, Folder: A, B.

The Mark Favorite command is available because just one folder, A, is selected, and there is no favorite group consisting of just A.  If you select Mark Favorite at this point, it would create a new favorite group Folder: A.

[3] "If you open the drop up list under the Grid view, A appears in the Favorites section"

The source-indicator pop-up shows two favorite groups, Folders: A, B and Folder: B.

[4] "but at the bottom of the drop up list you get the Add Favorites command although that folder is currently selected and already marked as a favorite."

The Add Favorites command is available for the same reason that Mark Favorite is available in the right-click context menu: There is just one folder selected, A, and there is no existing favorite group consisting of just A. If you click Add Favorites at this point, it will create a new favorite group Folder: A.

Folder A's icon in the Folders panel is marked with a star because A is contained in an existing favorite group, Folder: A, B.

[5] "So, on this side of the UI, A is a favorite but you can't unmark it."

A's folder icon is marked with a star because it is in favorite group Folder: A, B. To remove that favorite group (and the star on A), select both A and B, right-click one of them, and do Unmark Favorites. 

Alternatively, in the source-indicator pop-up, select favorite group Folder: A, B. Then click the pop-up again and do Remove From Favorites.