xdg-mime install /usr/share/applications/Azureus.desktop --novendor xdg-mime query default x-scheme-handler/magnet Azureus.desktop xdg-mime default qBittorent.desktop x-scheme-handler/magnet xdg-mime default Azureus.desktop x-scheme-handler/magnet gio mime x-scheme-handler/magnet Azureus.desktop gio mime x-scheme-handler/magnet vi ~/.config/mimeapps.list xdg-mime default biglybt.desktop x-scheme-handler/magnet ok maybe you need another trick to be registered, in my case I want back to biglybt as default so I want change defaults from qBittorrent to biglybt as in previous comment I changed defaults to qBittorrent . xdg-mime query default x-scheme-handler/magnet org.qbittorrent.qBittorrent.desktop 1 - verify that biglybt.desktop is in default and not any other vi ~/.config/mimeapps.list [Default Applications] x-scheme-handler/magnet=biglybt.desktop 2 - verify that biglybt.desktop is in default and not any other vi ~/.local/share/applications/defaults.list [Default Applications] x-scheme-handler/magnet=biglybt.desktop application/x-bittorrent=biglybt.desktop application/x-biglybt=biglybt.desktop x-scheme-handler/biglybt=biglybt.desktop 3- as root (as root) desktop-file-install /usr/share/applications/biglybt.desktop 4- as user run a register again xdg-mime install /usr/share/applications/biglybt.desktop --novendor 5- verify xdg-mime query default x-scheme-handler/magnet biglybt.desktop 6 - extra options all check gio gio mime x-scheme-handler/magnet Default application for “x-scheme-handler/magnet”: biglybt.desktop Registered applications: biglybt.desktop org.qbittorrent.qBittorrent.desktop vlc-plugin-bittorrent.desktop Recommended applications: biglybt.desktop org.qbittorrent.qBittorrent.desktop vlc-plugin-bittorrent.desktop 7- some commands that we may need xdg-mime default biglybt.desktop x-scheme-handler/magnet gio mime x-scheme-handler/magnet biglybt.desktop we may need remove files also from: ll ~/.local/share/applications/ ~/.local/share/mime/packages/ ~/.gnome/apps/ seems an old folder not used anymore and ~/.local/share/plasma_icons/ are icons from painel we should not delete anything from here ! .