I got the same error code: device error code 3 before and waste many BD disc.
After so many try and error, my solution is to set Transcode: Automatic with H.264 codec
I use 5d Mark III footage and it’s 1920×1080 24p. So in Encore – Asset -Blu-ray Transcode: I use “Automatic: 1920×1080 24p H.264” and then error code device error code 3 never happen again!
The problem is I change the transcode setting -Quality preset by myself, however encore cs6 might not accept those settings ( I guess).
Anyway, that’s just my personal experience, hope it can help.
Tom CHEN
雲朵婚禮 https://www.imemodvd.idv.tw