@gderf, this is most helpful, thank you! It seems that the AutoAdd plugin disables the built-in function. This makes complete sense, as they would otherwise interfere with each other. I had thought that the AutoAdd plugin was required to watch a folder; I didn't realise that it replaced the built-in...

Further note:
I manually changed ~/.config/deluge/autoadd.conf (while Deluge was not running) to remove all but the wanted folder (ensuring that it was numbered "1"), but the problem, including the error messages, persists.

Check the logs I didn't know where to find the logs, so I ran: deluge-gtk -L debug -l ~/deluge.log From deluge.log , I noted that the config entry for my auto-add folder refers to three different folders. The first two are noted as u'enabled': False — as they should be, given that they no longer ex...

Regarding the option Edit > Preferences > Downloads > Folders > "Auto add .torrents from" Whenever I start Deluge, for example after starting my computer in the morning, this option is always unchecked. It doesn't matter how often I check the option and press "Apply" then "O...

You open the torrent file to add it. 'copy of torrent files to' is an autoadd function for what to do after adding a torrrent file. In the add dialog point to the torrent data location. Thank you, I got it now! For my own future note, I'll specify exactly what I did. Put the torrent file into the &...

From a previous computer installation, I have the torrent file ( .torrent ), and the downloaded files, which were in a folder. I have placed: The torrent file into the reference-copies folder (the one labelled "Copy of .torrent files to" in the Preferences). The folder with the files into ...