After booting up my 2nd drive I start DVDitPro and check out the "Preferences".
Originally I had my Preferences set to delete all temporary files after transcoding and preparing the Blu-Ray disc image.
Unfortunately this meant that after waiting for a long transcoding to finish and then having the programme "crash" as it was doing from time to time - I lost all the work that had been done..... it was deleted during the "crashes"

Roxio's Forum members were able to advise me about the intermittent "crashes" and after defragging my discs all seem to be well again.
However the "crash" incidents made me thing again about selecting the "Delete temporary files....."
Later you will understand the reason for my not selecting it anymore.
I would also suggest that you make a special directory to keep the temp files in.
I have, as you see, made a DVDitJOBS directory on one of my drives.