Bad MacOS or bad external Apple DVD burner?

[Mac Hammer Fan]

My friend has an Imac 21,5 inch 2015 with Retina display. He is running MacOS Sierra. He has bought an external USB Apple DVD burner and has nothing but trouble.
1) in iTunes 2 of 3 CDs are faulty after burning the music on a blank CD. The CD is ejected before the burning process is finished and a message appears that the disc can not be written.
2) When he reburns a DVD recorded from his previous Mac with internal DVD-player, he puts the disc in the external USB burner and copies the disc to the desktop. Afterwards he copies the Audio and Video folder to the symbol of a blank DVD and burns the contents. But Apple DVD player doesn't recognize the new disc. Only when he chooses the DVD media by browsing in the disc he is able to view a movie.
3) We tried an application "Burn" but it is impossible to burn a DVD movie.
http://burn-osx.sourceforge.net/Pages/English/home.html
4) He considered Toast Titanium http://www.roxio.com/enu/products/toast/titanium/#system-requirements but it is incompatible with OSX 10.12
Is there anyone who has a solution or is it a bad OSX or a bad DVD burner?
I have no trouble with my internal DVD burner running 10.10 Yosemite...
TIA

 

[DeltaMac]

That support page for Toast Titanium is not yet updated.
The latest software update for Toast version 15 "This update resolves Mac OS Sierra compatibility issues and includes additional fixes for a range of issues.
That does NOT mean that Toast will fix a hardware problem with an external burner, if that is the case.

But, there's other software solutions, such as MTR, (used to be known as MacTheRipper years ago - good stuff!) which was recently updated to work better with Sierra.

 

[Fishrrman]

1. Try different media. I recommend Verbatim DVD or CD blanks.

2. Try a different burner. I've had great results with a Samsung BluRay/DVD/CD external USB drive.