Before when you could not delete these files did you happen to notice if you have anything uploading in the Total speeds: upload: or even the download: or were all fields blank with no activity?
Everything was finish. I notice that i'm able to delete the folder after start a new torrent, and finish it. I seem to solve the problems to delete the folder.
note : I reset the NAS, format all drive and start over, more thant 10 times during 1 weeks testing. I got the same result all the time !
I seem that the BT program sometime forget to add the "Delete" right. The only way to have this right appear, is to start some new torrent download, and when i click to remove the finish torrent, it seem to give the "delete" right to the torren i cannot delete. Also, i'm able to rename the folder of the download file (but not able to delete the file...weird).
Now when i got some torren i cannot delete, i'm waiting fiew download and try again.