This is pretty much a translation of a similar thread in the German forum but it should be helpful for the whole community and not only be limited to the German part of the forum. @kufo and myself had a pretty intensive exchange regarding that. Ich hope he will further comment my post regarding this. This started because we both had very bad experiences with dics generally available here in Europe. Very often the backed-up movies stutter at the layer break when there is the shift from layer 1 to layer 2. This can't be influenced anymore how it could be done when working with DVD-DL. The software is forced to fully burn layer 1 (the edge area is always very critical regarding quality and you don't want to use this area at all) and can only switch then to layer 2. For that reason we both imported 50 GB dics with a good reputation from Japan. https://geizhals.eu/verbatim-bd-r-d....html?hloc=at&hloc=de&hloc=eu&hloc=pl&hloc=uk Unfortunately we still had issues when burnt with the most common LG and ASUS variants. kufo then made some backups with his Pioneer BDR-206 and the results worked much better. So I purchased a Pioneer BDR-209 and started my trials. Well, even with the Pioneer burner it didn't work flawlessly burning at highest speed (10x). However, we have achieved the best and until now flawless results with the following combination: Disc (Link see above). Media Code: MEI-T02-001 Drive: Pioneer 206 / 209 Burn speed: 4x The LG / ASUS drives are excellent readers and "UHD-friendly" to backup UHD discs. They are lousy burners using BD-DL 50 Gb discs. The Pioneer drives are not "UHD-friendly" and lousy readers but burners with a good strategy burning BD-DL 50 GB and therefore currently the best solution for people who want to make their backups of UHDs on BD-DL 50 GB (BD 25 GB are a non-issue. LG / ASUS burners and 25 GB discs work OK with good discs, e.g. Verbatim CMCMAG-BA5-000 and burns are perfect even at max. burn speed). Recommendation for folks who want to make their UHD backups on BD-DL 50 GB discs: Verbatim Japan discs, Pioneer burner and limit burn speed to 4x speed.