Are using DVD-RW (+RW) media and/or "write Once" media (-R, +R)
And does it work in "normal" mode?
Flash drive is same as DVD-+RW in that you can OVERwrite a file, can not truely delete a file on DVD-R,+R.
What program are you using, Myself I use the freebee "Imgburn"
I use the build in CD burner of my acer computer. It used to work for many months to back up data. I do not know why it "suddenly" does not function any more. DVD used DVD-R