This issue has resurfaced with Island Living patch, when sim that wears particular custom item becomes covered in shiny squares. This happens on lower graphic settings. Particularly on my PC I was able to catch this glitch when I started the game on Ultra settings and then switched to lower (anything lower Ultra) graphic settings. Whenever I started the game on Low settings I could not see this glitch. Also, it is difficult to find glitchy content when you have to go in the game each time, when in CAS it looks absolutely fine because CC in CAS is rendered with 2048 px resolution, and CC gets shiny only when rendered in resolution 1024 px and less (all graphic settings except Ultra).
I came up with solution how to fix these kind of files, and how to find them in CAS without going each time in the game. By the way, this way you will be able to find not only shiny CC, but the one that makes your sim pitch black. I don’t have a solution how to fix black files yet.
Disclaimer: there might be a batch fix soon, but I don’t know how soon and whether developers of Studio in general have any time for it or is this batch fix easy to implement. So if you can’t wait feel free to use my method.

Also, please don’t blame creators whose content stopped working. EA changed something in how game processes the files, that’s why we got this glitch. We can fix it, not a big deal.
1. Start your game and check graphic settings. Set Ultra (the highest) settings. Apply changes and restart the game. It is important to start the game with ultra settings, not high, but the highest.
2. Run your game and load CAS. Now go in Settings -> Graphics -> Low. Choose the lowest graphic settings and apply them.

3. Check your custom content. Remove every single piece of clothing, even Maxis one and check custom clothing, make up, hairs one by one. Save them on your sim and use Sims 4 Tray Importer to find this content in Mods folder. Use Aveline’s video tutorial as a guide if you are not familiar with this program. Of course if you have thousands of CC pieces it will be a time consuming process. I’d suggest waiting for batch fix then.
4. Now it is time to fix this content. I noticed that all glitchy content had 2 things in common: it was made between 2015 and beginning of 2018 (2019 content is fine) and had blank specular on Studio tab. For this you will need to have the latest version of Studio.

In order to fix these files you need to import my blank specular. Download and unzip these 2 files somewhere on desktop or any other folder. Click on Specular and import my blank specular. Studio will import both files at the same time, it knows what to do, don’t worry. Save the file. That’s it. Do with every single faulty file that you found.
Note for CC creators: I checked how “Make Blank” button in Studio works in current version and it didn’t affect my content. But I still always recommend using custom blank specular (completely empty specular.png and alpha channel from your main diffuse in specular.mask file) if you don’t want any shine on your mesh. As you see it was perfectly working in the past, but with every patch EA implements some changes that affect how CC is read by the game..
If you never used Studio before and it doesn’t want to work on your computer, refer to this troubleshooting guide. This program has been tested my hundred thousands of users, so if it doesn’t work, it means that you didn’t install it properly.
If you have any other questions about this mini-tutorial feel free to ask.
July 14, 2019 at 9:44 pm ·
I'm sorry, I'm new to the Sims 4 studio. How do I open the package files of the broken CC in the studio? Like, I don't understand how I get them into the studio in order to import your blank specular.
July 16, 2019 at 6:44 am ·
Just double click on the file and it will open in Studio with viewport and Studio tab (the one that you need). Watch this tutorial from 10:04 to see how to import texture, but note that you need to import in SPECULAR field, not in diffuse. It is just an example of how to import textures in general. I don't have time to make a video tutorial, unfortunately. Otherwise I would do it. But it is super easy, I promise. You can duplicate your file to desktop before editing, so you will have a back up version.
https://youtu.be/mSpOCyS2G-U?t=604
July 30, 2019 at 8:06 pm ·
hey! i love the tutorial but i'm stuck on something.
the .zip file contains 2 files: "spec" and "spec.mask". which one should i import when clicking on 'Specular' tab on Sims4Studio? I'm confused
July 31, 2019 at 12:56 pm ·
Hi! When you click on spec, the second file (spec.mask) gets imported as well. Studio knows how to import these textures in specular resource. I never tried but I think studio will import correctly even if you click on spec.mask.
August 1, 2019 at 6:43 pm ·
Hello,
I’m stuck trying to fix my CC with your tutorial but I’m deeply confused. The blank specular file is PNG, how do I import that file? Also the layout you pictured in this tutorial is way different. I’m completely stumped, please help
August 4, 2019 at 9:17 pm ·
Hello,
Blank specular suppose to be either in .png or in .dds, it doesn't matter what format is used. I always use .png because it doesn't lose quality if I need to re-open it, when .dds loses quality like crazy after re-opening and re-saving. This tutorial is made using the latest version of Studio for PC which is Wishes 3.1.2.6. If you have a version that looks way different it's either some deprecated old version or may be MAC version (I've never seen it and never worked in it). However, you still need to find where to import specular. Look for tutorials online then.
September 1, 2019 at 12:30 am ·
TY SO MUCH!!! <3
September 3, 2019 at 8:03 am ·
wow, thank you so much! that has fixed my CC! It was bugging me so much because I just couldn't figure out what was wrong! I thought the shine could come from the specular map but as it 'appeared blank' I didn't think anything was wrong with it! :<
However, I have another question! It has fixed the appearance of the sim but the 'mood indicating sim' in the interface is still affected by the shiny glitch? Any ideas how to fix the interface one?
September 5, 2019 at 12:59 pm ·
Delete localthumbcache file from your C:UsersUserDocumentsElectronic ArtsThe Sims 4Mods folder, and game will generate new thumbnails.
September 5, 2019 at 12:59 pm ·
You are welcome!
September 17, 2019 at 1:58 pm ·
i couldn't do it 🙁 how can i do this without knowing which one is causing it?
September 18, 2019 at 10:05 am ·
Just look what is on your sim, take piece by piece down in CAS and see what is causing the glitch. You have entire tutorial explaining how to find glitchy content. I don't know what else to add.
October 31, 2019 at 1:14 pm ·
Hello, first thank you so much for this tutorial and sorry for my bad english. I have a question – I have hair that gives me the problem above but for this hair I have some recolors or retextures do have to fix only the original mesh?
November 1, 2019 at 10:08 pm ·
Hi! Your English perfect, so no worries. You need to fix that file that gives you issues. If your sim wears a recolor then it is a problem with recolored file. But to be honest I would check both files.
November 6, 2019 at 9:24 pm ·
Sorry but I have to ask again, could it be that CC I didn't create myself would not show up in sims4studio like it is described above.
I am missing the tabs Studio and Warehouse.
https://imgur.com/a/4zevTYU
And that's why I cant find the specular because it is supossed to be found under the Studio Tab
If it is like this I understand we shouldn't mess with the cc others created but if not do I do something wrong
November 11, 2019 at 11:22 am ·
Does this file have S4S Manifest resource? If yes then it is a merged file. You need to un-merge it via Content Management -> Un-merge. Choose folder where you want to un-merge your files and run Studio.
November 15, 2019 at 9:14 pm ·
Thank you so much for all the help. It is am merged file 🙂 now I know what to do. Have a wonderful weekend
November 16, 2019 at 10:08 am ·
Thank you! Have a wonderful weekend too!
November 17, 2019 at 2:44 pm ·
Hey! This is really helpful, but I'm not able to save it when I press the save button. Anytime I press it, a popup comes up and says "Unable to save in your game folder" Do you know how I could fix that?
November 18, 2019 at 8:21 am ·
You can't save files in game folder like The Sims 4/Bin. Only to your Mods folder. You are saving to the wrong folder.
November 28, 2019 at 10:28 pm ·
Thank you! You are geat!
December 6, 2019 at 4:57 am ·
Thank you! Do you have to replace the specular for every swatch, or will S4S apply the new specular to all the swatches automatically?
December 9, 2019 at 8:56 am ·
Thank you!
December 9, 2019 at 8:58 am ·
Studio does everything for you. When you import specular it's instance number appears in every CAS part resource automatically.
December 22, 2019 at 2:36 am ·
Hello, can you please provide more detailed instructions on how to edit a cc item in sims 4 studio. (Or direct me to a video). I was able to identify the shiny cc. However, I cannot figure out how to navigate to the sims 4 studio screenshot (with studio tab, warehouse tab).
What I've tried so far is choosing the recolor option under CAS in sims 4 studio. Then it takes me to a page with all of the cc. When I try to select an item, the system prompts me to create a new name as if I'm making a new item. I'd like to simply edit the existing item so that I don't have to redress all of my sims with the shiny issue.
Thanks for your help!
December 28, 2019 at 3:32 am ·
You can edit the file via "My projects" button and selecting the file or double clicking it. These are the only 2 ways to edit existing .package.
January 13, 2020 at 4:17 am ·
To all people who I had a conversation with regarding black textured sims. These comments are not present here since I backed up and imported blogspot posts at the beginning of January, and I could not transfer these posts manually here, unfortunately. I edited 102 posts spending solid 15 hours, so I didn’t want to risk it and trying to back up one post with recent comments. I am still figuring out what is the best comment system to implement on the website.
January 14, 2020 at 7:45 am ·
No problems… (one of those was me) – if you do figure it out, though, let me know. 🙂
January 19, 2020 at 5:19 pm ·
I’m not sure exactly which blank package to import. Doing this has now made the sims that weird checkered question mark color.
February 8, 2020 at 8:34 pm ·
It is impossible to get a checkered mark by importing the texture. Question mark means a missing texture, which happens when you remove resources from Warehouse tab or you work with the .package that was created in a weird way (happened long time ago when one creator was deleting resources in order to break .packages the way that people would not be able to recolor it).
July 29, 2020 at 6:10 pm ·
Thanks so much for this and the files, however, there are definitely some steps missing from the instructions, and with the newest version of Studio (2020) the screen doesn’t appear and it doesn’t give you the option to import files. At least in the area, I could get to. So unfortunately I’m just deleting the CC. This is too much hassle for a couple hairs and a few items of clothes. Good luck everyone!
July 30, 2020 at 7:02 am ·
I don’t know what else to add to the tutorial. I documented every possible step spending hours putting everything up, testing, writing, taking screenshots of every single step. There is nothing else to add. Tons of people were able to follow the instructions and fix the files. And there is nothing that has changed in Studio in 2020, it has the same interface and functionality. Literally.
August 19, 2020 at 4:54 am ·
Thank you so much for this tutorial! I actually made your wonderful tutorial work inspite of my enormous CC folder: if you remove the thumbnails with the sims4studio batchfix before following your tutorial (make a copy beforehand if you want to keep thumbnails), you see the shine in the thumbnail on the panel. I’ve found everything that adds shine, and the most tedious part is then replacing the specular. Thanks again so much!
December 8, 2020 at 12:14 am ·
Hi, I followed all the steps exactly… twice, with multiple different cc. No changes to any of them, all still shiny/glitchy, does this still work?
December 9, 2020 at 1:09 am ·
Hi. Yes, it should work. Upload your updated (the one that you fixed) .package and I can take a look. Is it shiny in CAS? Are you absolutely sure that this is the particular piece of CC that is glitching?
December 10, 2020 at 3:22 pm ·
Yes I’ve tried using the CC on naked sims & also most of them have been glitchy for months but I didn’t want to delete bc I like them a lot. It’s shiny in cas but sometimes isn’t. Like I will choose it, maybe it will be shiny maybe not, but if I click on & off it a few times or switch between swatches guaranteed it will come out shiny like 80% of the clicks I make. Thank u so much, where can i upload the package to?