[Asterra]

Preface: Using Nvidia Shield.

The plan with this device is that I will be regularly plugging in and removing drives, depending on what media needs to be watched at any given moment.  I have already noted that when I remove a movie source, Kodi will continue to assume everything that was on that drive is still available, unless I actually select one of those movies, at which point it will ask if I want to remove it from the list.

I'm afraid of removing things from the list, as I don't want to have to go back through the menus to re-add it all, and risk Kodi scraping over the artwork I've already put there.

What I was really hoping would happen: Kodi remembers a given drive and what was on it.  When I remove the drive, it removes that drive's media from the browser.  But it doesn't forget it.  When I bring the drive back, Kodi re-adds the content folders, makes note of any additions / removals, and updates the movie list appropriately.  Without requiring me to manually re-add anything.

This isn't some fancy new idea I just thought up.  It's how it works on Popcorn Hour and other media players I've tinkered with.

[Karellen]

When I remove the drive, it removes that drive's media from the browser.  But it doesn't forget it.  When I bring the drive back, Kodi re-adds the content folders, makes note of any additions / removals, and updates the movie list appropriately.

Nope. Cannot be done as is. Someone would need to re-code to enable that function.

I'm afraid of removing things from the list, as I don't want to have to go back through the menus to re-add it all, and risk Kodi scraping over the artwork I've already put there.

Kodi does not overwrite local artwork, unless you specifically run an Export and enable the option to overwrite artwork. But during the normal course of scraping, artwork will not be overwritten.

This isn't some fancy new idea I just thought up.  It's how it works on Popcorn Hour and other media players I've tinkered with.

Sure. If that is how they work, and you really need that feature, stick with them.

The plan with this device is that I will be regularly plugging in and removing drives, depending on what media needs to be watched at any given moment.

Alternatively you could bring yourself into the current era and use a NAS

[Asterra]

Nope. Cannot be done as is. Someone would need to re-code to enable that function.

That's that, then. If there's one thing that I've come to realize about Kodi, it's that if something has existed in other media players for a decade but still isn't part of Kodi, it never will be.

Kodi does not overwrite local artwork

What I'm worried about specifically is that if I'm not careful about how I add (or re-add for the umpteenth time, as the case may be) source folders, Kodi may decide to scrape new artwork to wherever it scrapes that stuff (I still haven't figured this out, or even where the setting for that can be found), and then from that point on it will elect to use the artwork it's personally scraped, as opposed to the local artwork that was already there, ultimately requiring me to, say, delete the movies database file outright in order to work any kind of solution. I've had to do this on pretty much every occasion something has been plugged in in a way that I had no control over. For example, back when I made attempts to use Artwork Beef, the stuff it grabbed was irreversibly referenced from that point on, and this was a problem, because after using that add-on, every time Kodi would enter movie browsing mode, instead of displaying all the box art instantly as it normally does, it would show a blank library, as it was evidently trying to load something and for whatever reason that process was taking it between 5 and 10 seconds to complete. (I gave up on Artwork Beef because of this and some other reasons.)

Sure. If that is how they work, and you really need that feature, stick with them.

Popcorn Hour and similar options have the distinct negatives of being behind the times and also not open-source, the latter of which meant for example when it turned out that my A-300 could not play some MKVs without steadily losing audio/video sync, no fix would ever be forthcoming, which in turn forced me to convert all MKVs into M2TS since the player had no similar issues with that container. Still, when we bought those devices, they were almost uniquely capable, and I will note in particular the fact that they could handle NTFS just fine, as that was pretty much the deciding factor.

Alternatively you could bring yourself into the current era and use a NAS  

Scenario: One Nvidia Shield, which must be moved between any of three display devices depending on the current needs. Although ethernet has been run through the walls, it is effectively non-existent, because the idiots who installed the land lines made use of them to do it, without telling anyone, and the land lines were only recently gotten rid of. The point being that the device will be moved around regularly, and that means things will be often plugged into and unplugged from it.

[Karellen]

Kodi may decide to scrape new artwork to wherever it scrapes that stuff (I still haven't figured this out, or even where the setting for that can be found),

Nope, it wont "just" decide to change its coding. Kodi ALWAYS prefers local information. When it cannot find local, then it calls up the scrapers and locates that information online. If your artwork is correctly named and saved in the correct location, Kodi will use it.... always. There is no setting for this. This is the way it works.

For example, back when I made attempts to use Artwork Beef,

Artwork Beef is not for all users. It sounds like you and I are quite similar in that we take great care in curating our libraries. If that is the case, then the ONLY reason you need Artwork Beef is to load local Movie Set Artwork (but this becomes core function in v19, so Artwork Beef will no longer be needed by us). So if you have it installed, disable everything except the Movie Set Artwork component.

Import-Export library (wiki) wiki page may be of use to you.

[Powerhouse]

Maybe not exactly what you want, but Kodi can "Sorta" do what you ask. If you remove a drive, you need to re-scan your library, then Clean the library, and this will remove the missing Movies. Once you plug the drive back in, you simply re-scan your library, and it will put all the Movies back from the drive (as long as you haven't removed the drive as a source).

The only problem with this, is the time it takes Kodi to re-scan and clean the system, and then re-scan again.

As for Artwork, if you setup your Sources to use "Local" artwork, then you lose nothing when you perform the above re-scan.

Hope this helps.