Comment 4 for bug 959616

I did a fresh install of 12.04, but kept my home directory intact. After quitting transmission, completely removing my transmission settings folder and starting transmission again, I no longer get this error.

rm -rf ~/.config/transmission/

I should have moved it aside, rather than remove it, so I could see what setting was causing the error. I'm guessing something to due with the download location even though I was saving everything to my home directory and still getting this error.