I am on 0.1.30-1ubuntu and I just got this issue as well. I was unable to unmount a volume because tumblerd was generating thumbnails, even though I had no Thunar window open. I found it by running fuser, killing the process allowed me to unmount.
I am on 0.1.30-1ubuntu and I just got this issue as well. I was unable to unmount a volume because tumblerd was generating thumbnails, even though I had no Thunar window open. I found it by running fuser, killing the process allowed me to unmount.