Edit: EA has now released a patch for fixing the hair color problem. It's no longer needed to use this workaround fix. After installing this new patch, all CC hairstyles should be functioning correctly again.

The november 2018 Sims 4 patch has unfortunately broken a lot of cc hairstyles. The hair colors can't be changed anymore. This problem is caused by EA trying to fix the matching of eyebrow colors with hair colors. Unfotunately with the result that this has broken the use of non-standard hair colors.

The current situation is that EA has said that they are looking into fixing this problem in their code. But at this moment they haven't made a fix public yet.

There is however a workaround solution known, that will at least allow you to continue to keep using your downloaded hairstyles. But it's important to realise that this fix will set all your downloaded hairstyles to be allowed for random use in your game (meaning that they can show up on randomly generated sims in your game).

The programmer of TSR Workshop has added a batch fix option for this to the TSR Workshop program. You can download TSR Workshop here: https://thesimsresource.com/workshop/

Once downloaded, move the installation file out of the zip file and run the installation. Follow the steps through the installation as will show on your screen.

When the installation has been completed, start TSR Workshop en follow these steps:

1. Go to Edit> Preferences > Folders and set the path for the Global folders for Sims 4 Data to your Sims 4 folder in your Documents folder. This will for most people be something like C:\Users\YourName\Documents\Electronic Arts\The Sims 4. Click on the Apply button once you have set it.
2. Make a backup of the custom content in your Mods folder.
3. In the menu, go to Tools>Sims 4 November 2018 Patch, Hair Batch Fix. You will now get a warning about making a back-up, so make the back-up if you haven't done yet at this point.
4. Wait for TSR Workshop to go through all your installed hairstyles to set the random setting to true for each individual color option. Depending on how many hairstyles you have, this can take a while. TSR Workshop might temporarily show as "no reaction". Just let it run for a while.
5. Once the fix is done, a pop-up will show up with the amount of hair color options that have been fixed.
6. TSR Workshop can be closed again after this, and the hairstyles should function correctly again in your game.

Once again, this is actually a workaround fix. Having all your hairstyles being used random might be something you don't want in your game. Once EA will come with a real fix of their code, you can place the backups of your hairstyles back and remove the ones you have just fixed.