Just discovering the 'Tray' Folder :(

From previous (unfortunate) experience, I've deleted tray files to save space however on reloading the game noticed that all of my saves have gone and I have been devastated. As you mentioned in the original post you are aware of this, but as far as I can figure out there is no definitive way to judge which of the tray files correlates to your library files. You could try deleting some sims families you don't want anymore individually and then checking if any files are missing from the folder but writing down the file names? Normally, I delete the screenshot folder only and then delete various things in-game so I know exactly what will be going! In my honest opinion, I wouldn't delete the tray files unless you want to risk losing your entire save file. There may be others who are a lot more savvy with this than me, of course. I just didn't want you to lose however many hours you've put into your game!

Don't delete your Tray . thats where all saved sims and saved houses go. Unless youve saved them to the Gallery they will be gone forever. As far as I'm aware, it shouldn't slow your game.

I believe there is a program called Tray Exporter which can look at your tray files see which correspond to what and export stuff you want to keep. I haven't used it myself. If you are feeling adventurous, what you could theoretically do is use this to export stuff you want to keep but don't want to upload to the Gallery for some reason and rename the folder and see if it helps. That way you can replace it if something goes wrong.

The easiest thing to do, without getting technical, is to just delete households and lots from your library in game. It will delete the files from the tray folder in the process.
Or you could make a backup of the entire tray folder somewhere on your hard drive or on an external drive and then start deleting the things you think you won't use anymore. That way you can still get back everything by putting the files from the backup in the tray folder.

I have a habit of going through my tray folder from time to time and backing up every creation seperately, but that is a somewhat technical process. It isn't really hard once you get the hang of it, but it is a bit of a dull task, you just have to keep an eye on the time stamp of the files and retrieve the right trayitem file (if you've shared a creation to the Gallery, or updated its description, it may get a different time stamp).
I think this is the easiest tutorial: http://lorisims.net/tutorials/english/sims-4-export-of-lots-and-sims/ (personally I skip the uploading and downloading from the gallery part, but it's probably easier, but more time-consuming, to do it this way). This is also a good one, but the explanation is limited to lots (though, you can use the same method for households and rooms): https://jenba.tumblr.com/post/121635635022/how-to-extract-tray-files-for-upload This one doesn't use the Gallery.

In reaction to the comments above, messing with the tray folder should not normally affect your saves, those are completely different files, in a different folder.
And having a very full tray folder (just like the screenshots folder, saves folder, cache folder) can slow down your game or even cause issues.

It is probably a good idea to make it a habit to clean the cache folder and delete the localthumbcache.package file after every play session. And make regular backups (I usually do them before every patch, so approximately once a month) of the saves, screenshots and tray folders (and mods folder, if you use mods).

"MDianaSanders;c-17287833" wrote:
The easiest thing to do, without getting technical, is to just delete households and lots from your library in game. It will delete the files from the tray folder in the process.
Or you could make a backup of the entire tray folder somewhere on your hard drive or on an external drive and then start deleting the things you think you won't use anymore. That way you can still get back everything by putting the files from the backup in the tray folder.

I have a habit of going through my tray folder from time to time and backing up every creation seperately, but that is a somewhat technical process. It isn't really hard once you get the hang of it, but it is a bit of a dull task, you just have to keep an eye on the time stamp of the files and retrieve the right trayitem file (if you've shared a creation to the Gallery, or updated its description, it may get a different time stamp).
I think this is the easiest tutorial: http://lorisims.net/tutorials/english/sims-4-export-of-lots-and-sims/ (personally I skip the uploading and downloading from the gallery part, but it's probably easier, but more time-consuming, to do it this way). This is also a good one, but the explanation is limited to lots (though, you can use the same method for households and rooms): https://jenba.tumblr.com/post/121635635022/how-to-extract-tray-files-for-upload This one doesn't use the Gallery.

In reaction to the comments above, messing with the tray folder should not normally affect your saves, those are completely different files, in a different folder.
And having a very full tray folder (just like the screenshots folder, saves folder, cache folder) can slow down your game or even cause issues.

It is probably a good idea to make it a habit to clean the cache folder and delete the localthumbcache.package file after every play session. And make regular backups (I usually do them before every patch, so approximately once a month) of the saves, screenshots and tray folders (and mods folder, if you use mods).

That's really useful to know, thank you! :) I've gone through the My Library bit and deleted a lot of things - it took forever, but was definitely the easiest way, and it does seem to have reduced the files in the Tray folder as well :)

I think, now I know it exists, I'll make sure I keep up to date with deleting My Library items, and maybe explore creations and corresponding Tray files when my brain has some space ;)
Thanks for your help!