Thanks Crin,
I purchased the Horse Ranch EP and encountered the same problem with Chestnut Ridge not opening so I finally bugged my husband about it. He followed the steps above and the pb wasn't resolved until I remembered about the MODS! We disabled the mods and Viola! Both San Sequoia and Chestnut Worlds were there. I didn't think that the mods were the problem because I play on an older Pc as well, with mods and the worlds are just fine.
DOES THIS MEAN I CANNOT USE COOL MODS ANYMORE?
Just for the sake of confirming, I enabled the mods and San Sequoia and Chestnut Ridge were gone. I disabled it and the worlds were back.
Thank you and if there are any tips that would allow some mods to be used, that would be wonderful. 🙂
Right now, I am happy to get into San Sequoia!