Everytime I rebooted or logged out and logged back in, it asked for my owncloud password, showing the message “Reading from keychain failed with error: ‘Could not open wallet: other; Failed to execute program org.kde.kwalletd: No such file or directory'” Of course, I am on a linux mint 19 fresh install, on cinnamon, without anything KDE related. Point is that This owncloud client need to communicate with gnome-keyring, which I had it installed. There was one missing package, called libgnome-keyring0 ( GNOME keyring services library) which after installing it, solved my problem (and owncloud’s password was automatically saved on “Passwords and Keys”, the gnome-keyring’s GUI. Double check if the package libgnome-keyring-common is also installed.