Just like the header says, I have multiple cc named like this. I don’t know why they are, they just came like that. For example: mailbox-rcpackagepackagepackagepackagepackagepackage.package. Whyyyy? And will it crash the game because the game is going to be confused? Thanks!

Do you know where you got it from?
I don't know nearly enough to be the person that tells you yes or no but I myself would also be suspicious about something like that.
You could always rename it to something normal but I would be suspicious of why it was named like that in the first place.

I'm thinking that it could be harmless, but that is one long text string... I don't think it will crash your game, I think the worst thing that could happen is that the CC just won't work, but someone may correct me on this. I have package files that are literally symbols and the content loads fine. I just can't zip my folder with those files in, as my computer doesn't recognise the symbols...

Where did you download these CC? If we know what content it is, where you downloaded it, and even the name of the creator, people could be able to compare their files to yours. If the same content is named differently in someone else's folder, then we can know if something went wrong in the download or not.

Pretty sure this is the sort on nonsense the default installer comes up with. Use Clean Installer instead. As for crashing, no idea, but it wiil do absolutely no harm to rename it.

I think you're right. I do use clean installer, though, so maybe something went wrong. Time to go on a renaming spree...

If I were you I'd get rid of all the extra mailbox and trashcan recolors - or at least find them and put them in a separate folder so they can be easily removed if you ever want to package lots - because EVERY SINGLE RECOLOR will latch onto EVERY SINGLE LOT, even if they haven't been used, and I really do mean every single recolor (which can be upwards of hundreds if you haven't cleaned out your lots ever). They're an especially big issue if you have the buyable mailbox/trashcan mods (these too will latch onto lots, by the way).

These days if I ever download a lot with any CC attached, I go through every piece of CC and remove the mailbox/trashcan files. I take care of what I can in Clean Installer (the texture files tend to be recognizable, but there are a few iffy ones), and sort out the rest in SimPE by opening the files I'm unsure of.

Weirdly named files are always suspicious ones, along with the packagepackage ones, but a few get normal filenames, too. I have found somewhere between 100 and 150 in single lots, so these can be very annoying buggers.

I have found over 1000 files of trash on downloaded lots. Mostly mailbox-trashcan files but there are also over 170 recolors of one object (when you need only one) and many similar objects with recolors(like 40-50 pillows). I usually unpack with Clean Installer into empty downloads folder and then will get rid of trash. If this is item you need just delete additional .package(s) from filename.

^ That, too. I think if you have the CEP it also includes recolors of certain objects. I have a really old, large set of recolors that really likes to add itself to lots, and this seems to be the only logical reason why. I'm not sure if it goes for all CEP objects (I don't think so, it's just some random items), but I have noticed some tend to be very clingy. Maybe it's whenever those items are used in the build.

Good to know. I found a crap-ton of them and chucked them aside.

Multiple "package" extension files I get from installing Sims from other people. I use Bulk Rename Utility to rename them.

I believe an old version of Clean Installer was the culprit in adding those multiple package extensions. It's been fixed for a number of years but some older files still show the results from it. When I find one, I simply reduce it to having a single .package extension and go on. Having multiple .package extensions isn't harmful on its own although some programs may not process the files right and having those extra characters in the filename could cause problems should you exceed the 255 character limit for a filepath.