Comment 1 for bug 510801

I have just tested here and it worked just fine:
1. I added a torrent file to the list
2. In torrent addition dialog, I edited the save path to point to the folder where I already have the file
3. qBittorrent started checking the torrent and went to 100%, then started seeding.

The issue may be a side effect of another feature. For example, are you using a different folder for incomplete torrents? Did you label the torrent (and did you enable the feature "Append torrent label to save path"?)? What version of libtorrent are you using exactly?

Did the torrent contain a single file or does it contain a root folder with files in it?