Delete CC Thumbnails

Hello!
What thumbnails exactly? the "swatch thumbnail colors", "custom thumbnail" or "catalog thumbnail" ?
Here is a print of the program:

If it's the catalog thumbnail the game will auto generate it when you select the object in build/buy mode
The custom thumbnail is just an image that is an alternative to the swatch thumbnail colors (the little icon you see when you are choosing the recolor)
But if you deleted a swatch you will need to add it again, select the texture, thumbnail color or custom thumb
If it's a texture from an object/cas from the game you can create a new project just to pick the texture
Sorry I didn't understand your question well XD

Look in your Documents/Sims 4 Studio/Batch Fixes folder. There will be a backup folder in there with the date and time that you ran the batch fixer. The folder will contain every .package that Studio edited to remove the thumbnail in its pre-batch fix state. They will be arranged however you had them arranged so if you were using sub folders that structure will be maintained in the back up folder. Place all of the originals back into your Sims 4/Mods folder to overwrite the ones that had the thumbnails removed. I recommend using Copy/Paste rather than just moving them. This way you still have the backup version safe. Once you've checked that you've replaced everything properly you can either keep the backup or delete it.

All of Studio's batch fixers create a backup of the original .packages before getting started on any changes to the .packages.  You can always restore your Mods folder to the pre-batch fix state by digging out the originals from the backup folder

Hello, I understand now. Tried to do the same thing and the solution from orangemittens worked (But there are some folders missing in the backup, don't know why)
Folders missing in my case: "shoes", "scripts".

Sims4Studio Batch fix folder location:
(Check the date you did the Delete CC thumbnail, to locate the subfolder, inside the Batch Fixes folder)
If you are using windows
C:[or where you installed the operating system] -> Users -> [username] -> Documents -> Sims 4 Studio -> Batch Fixes -> [year-month-day_hour-minutes-seconds] -> Backup

Hinayuna, if Studio did not fix a thumbnail in a given folder than it will not make a backup of that folder. Scripts do not have thumbnails and, it seems, your shoes folder didn't contain any files that needed a thumbnail removed. This is why neither of those folders showed up in your Backup files.

annett85, Studio does not alter .package files through the batch fix process without first making a backup. When you selected the batch fix you ran a popup appeared before the batch backup and batch fix processes occurred. This popup allowed you to choose where the backup folder would be placed. It looked like this:



The line indicated by the blue box determines where the backup folder was created. The backup folder is located wherever you chose for it to go based on what was in that line. That is where you will need to look for your backup folder. If you don't recall what you put in that line you may need to search your computer for the backup folder but it is there somewhere...Studio will not begin the batch fix process without first making a copy of the file it is going to fix.

So, I decided to delete my CC thumbnails but it looked weird so I wanna install my CC thumbnails again. Please tell me how to do it.
(Excuse my bad English)

I have the same problem,I accidentally deleted them but cancelled it so it deleted them but it didn't save a backup so I have no idea how to retrieve them?