Have you recently added a new Expansion or Stuff pack and found its all gone wrong?

Make sure custom content is ENABLED after adding a new pack! Later packs tend to disable custom content by default so you need to ENABLE it then EXIT and RESTART your game

Flashing Blue Furniture:-

This means you forgot to reinstall the CEP after installing your expansion pack! Make sure you get the latest version (regardless of what pack you have installed), run the installation, run your game and you should find the problem is fixed. If not follow Step 1 below.

Missing Clothes, Genetics & Make-Up:-

It is important when you add a new expansion pack to do it 'cleanly' - this means moving out all of your downloaded content, creating a back-up of your Sims and their neighbourhoods and then adding the EP, running your game to the neighbourhood view, allowing it initialize properly before adding your custom content back to your game files. Chances are if you are reading this, it means you didn't do this!  

Flashing Red Walls, Floors & Terrain paints

This is unfortunately caused by a change in the graphics card requirements between earlier and later expansions - you can find more information about this issue here in our FAQ. Its not caused by installed custom content or the way in which you may or may not have installed your new EP, but is a feature of the EP itself.

Step 1:

Remove everything from your Downloads folder and your Saved Sims folder if you've been putting skins files there by moving it to a different location on your computer. Run your game to the neighbourhood view, start a new lot - you don't need to create Sims to move into it unless you want to, enter the lot and then SAVE and EXIT.

Now add your downloaded files back to your game folders - RE-INSTALL the CEP (make sure you have the latest version, especially if there is a new one which supports the EP you have just installed), and return to your game, choose one of your usual families to check whether the problem has been solved. If it has NOT been fixed, do NOT save your game when exiting.

Repeat this step a second time, if it still fails then proceed to step 2.

Step 2:

What to do if Step 1 fails!

Often skins will still fail to be available even after trying the method above, if they are left in your game files when installing later EP's. I'm sorry to say that the only definite solution I know of is to reinstall your game from scratch and then add the items back in afterwards - if you are doing this please make sure you RUN your game once EMPTY before adding your content! Do remember also that a new EP/SP will often reset the 'show custom content' dialog and 'show custom content in catalogs' options - make sure those are set appropriately!

See here for details of how to re-install your game without losing your Sims and their homes!