[Karellen]

for example I made an Alien collection which includes both the original films and Prometheus and Covenant that eventually goes away.

I don't know how that can happen on its own because if the Collection is correctly made, then it stays.

If you are Refreshing your movies in that set, maybe you want to update your artwork or some other reason, then yes you will remove it from your home-made collection because the movie is rescraped with data from TheMovieDB. TheMovieDB have no idea what collection you have created.

If it is not that, then I have no clue and honestly I would be hard pressed to try and figure it out for you. You could provide a Debug Log which captures an Update Library, and I might spot something related to the issue. Also double check the wiki pages I provided to ensure you are doing it correctly. I have many home-made collections that I have had in my library for many years without any issue. (Alien/Prometheus being one of them)

[Shawzborne]

for example I made an Alien collection which includes both the original films and Prometheus and Covenant that eventually goes away.

I don't know how that can happen on its own because if the Collection is correctly made, then it stays.

If you are Refreshing your movies in that set, maybe you want to update your artwork or some other reason, then yes you will remove it from your home-made collection because the movie is rescraped with data from TheMovieDB. TheMovieDB have no idea what collection you have created.

If it is not that, then I have no clue and honestly I would be hard pressed to try and figure it out for you. You could provide a Debug Log which captures an Update Library, and I might spot something related to the issue. Also double check the wiki pages I provided to ensure you are doing it correctly. I have many home-made collections that I have had in my library for many years without any issue. (Alien/Prometheus being one of them)

I will try some things and see what happens, and get back to you if I have issues.

1. Issue may happen when updating a file’s quality then updating/clean may break the collection.

2. My movie sets are in physical folders

3. Before I used to use the fanart artwork downloader addon . It isn’t currently installed now.

I gave up on trying to make them for a while now. Will see what happens.

[Karellen]

1. Issue may happen when updating a file’s quality then updating/clean may break the collection.

Yep, that will break it when you rescan the new file into the library.

2. My movie sets are in physical folders

Same with mine. Won't make a difference to the Collection in Kodi.

3. Before I used to use the fanart artwork downloader addon . It isn’t currently installed now.

I don't think that addon exists anymore. Its replacement is Artwork Beef, but that should not affect the Collection.

Your best solution is to regularly run an Export to Separate Files. I run one every two weeks, and it preserves all the changes I make to my library (and I usually make quite a lot of changes).

Once you have these nfo files as backups, then you can move, replace, delete, re-add and whatever else you like doing, and Kodi will always reload the data from the nfo file exactly as you had it.

[Harro]

Any ideas how to make movie sets stay even after update and cleaning?

Once you create a Collection, it should remain. There is no reason for it do disappear just because you ran a Library Update or a Clean Library. Unless you mean you have completely rebuild your library, like on a new install, then yes these will disappear. Movie_sets (wiki)

If you want to preserve your library changes, then you need to regularly run an Export to Separate Files so your changes are saved to nfo files which are then used to rebuild your library.

See... Import-export_library (wiki)

Also of interest... HOW-TO:Movie_universe (wiki)

No I didn’t rebuild my library, collections made by hand while using a remote using the interface disappear or pull out of the tmdb sets eventually, for example I made an Alien collection which includes both the original films and Prometheus and Covenant that eventually goes away.

I have both those collections and made a new smart play list called New Aliens. 

[Karellen]

@Harro

Do you use the <sorttitle>Alien 01</sorttitle> tags for your collections? I notice the order of your movies are a bit off (well off for me, but you may want them that way)

[Harro]

@Karellen 
I don't use any tags. This collection is a collection of two movie sets. Alien collection and Prometheus collection. I won't keep this collection and will delete this playlist. Was just trying it out for a playlist and seems to work ok. I guess I could use a sort by date to straighten out the order. Been using more playlists lately and adding to the top of my categories either movies, tv or 4K.

Just try order by year and fixed.