I made sure I removed the original Mutske ones. The shorter Empty Billy bookcase on the other hand does allow more slots. Does the NekoSayuri Billy bookcase version work for you regarding more slots?
Link to download: https://nekosayuri.tumblr.com/post/...e-mutskes-billy

Depending on how you organize downloads from lots with CC, have you checked to see if any copies of the originals have snuck in there?

It is possible the files have a randomized string of letters/numbers as a filename (I think that's an issue if the lot files have at some point in time been installed with the default installer in your or other people's games). If you have any such files in your game, you can check them with SimPE, for instance the description.

Can also be a good idea to check the description of the item ingame. If it doesn't match nekosayuri's changed description, you have something interfering with their version in your game (last loaded item is usually the one that "counts")

@simmer22 I made sure I deleted the original ones, but I can always double check. The new ones do have the descriptions of NekoSayuri.

Do they work for you in your game?

Maybe you are trying to put something on the shelf that isn't "weighted" correctly?

I have those shelves and they work for me. I agree with HugeLunatic--perhaps the items you're using aren't weighted correctly? Are you trying with Maxis items or cc? Also, there are a couple (I think 3 to be exact) that Nekosayuri didn't add extra slots to, so make sure you're not using one of those.

@Phantomknight @HugeLunatic I recall I used both Maxis and CC deco. The item fitted in multiple slots in the Emptied Billy Bookcase, while it was restricted in the NekoSayuri one.

EDIT: I even checked with HDCU V2.1, and I haven't seen duplicates of Billy. And I haven't downloaded lots with CCs recently.

Is it all of the shelves or just one?

@Phantomknight I think all of them. For example, I have issues with not having more slots for the right one: https://64.media.tumblr.com/3c19c97...195xo1_1280.png

For now, I temporarily moved them out of my Downloads and want to try if they work again if I put them back. Could it be related to something with caches? And what about Override files? (I know the Billy one doesn't have overrides, but I wonder if it could be conflicting with other ones)

If you've had the old ones in your game (from TSR), try deleting the caches.

These should be standalone with new GUIDs (apart from the reused ones) so in theory they shouldn't conflict with other items other than the TSR ones, but there could of course be random items with conflicting GUIDS out there, but it's not too likely.

Can you post an image of how they look in your game, with all the slots filled with small-ish items that fit into the working slots?

I quickly checked the slot setup and it seems they're fine, but I haven't checked what kind of weight the slots can hold (a bit unsure how to - I know how to check/fix the deco items but not entirely sure of the container items).

@simmer22 attached you will find Leefish Billy bookcase on the left with proper slots (2015 updated FT version), and on the right the one by Mutske/NekoSayuri. The latter one is a bit wider. I used a Maxis object to stack the bookcases.

I tried several of the ones by nekosayuri, and I found the slot entries to be weird. They go up/down to each new shelf, and won't place left/right until you fill the center slots.

@HugeLunatic I just tried and I have the same thing indeed! I guess for now, I have to workaround with NixedSims slot blockers.

You can change slot placement with M - it can be a bit tricky still, but it's nice to know about it.

When you're filling up a shelf, it's not filled up entirely until the next item gets a red grid line, or ends up on the floor (depending on whether you have moveobjects enabled). Can be good to know if you're testing out slot placement.

I'm guessing they kept the original slot placement, then added the extra slots on the sides, so you can probably expect the all-middle then-sides placement for all the shelves.