Not sure if this is the right place to put this but basically, I've already downloaded the blockchain until Dec 27, but now when I open bitcoin core on my hp windows laptop. I got the popup saying this is the first time I launch bitcoin core, which it isn't, but then I selected the 'chainstate' folder on my external hard drive, hoping it would resume the blockchain but instead it started downloading everything from scratch again.
TLDR: Bitcoin Core is asking where to store the blockchain, despite me already having downloaded the blockchain until Dec 27,2020 and I am wondering how to resume the syncing from where I have downloaded. The program starts to redownload the whole blockchain.