By Juan Matías de la Cámara Beovide

Set Default Folders (Pictures, Music, etc.)

Default folders are the ones you can see in Files named Downloads, Documents, Pictures, etc.

To change the default folders (or to fix them, as was my case), you need to edit one configuration file. The file to edit is: /home/your_username/.config/user-dirs.dirs.

Open Files and press CTRL+H to see hidden files. In your personal folder find a directory called .config. Find the file and edit it with Scratch.

This file looks like this:
# This file is written by xdg-user-dirs-update
# If you want to change or add directories, just edit the line you're
# interested in. All local changes will be retained on the next run
# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
# absolute path. No other format is supported.
$HOME is your home directory (/home/YOUR_USERNAME). Simply change the name of the folder and that's it! You have a new "default" folder.

You can also choose the name you want. For example, XDG_PICTURES_DIR="$HOME/MyReallyCoolPictures" will refer to the folder called /home/YOUR_USERNAME/MyReallyCoolPictures.

NOTE: You can also change the location of your directories, but be careful!