The BD-R disc has stuff written on it, such as write speed, brand (Media Range), etc. K3b detected the disc but the write speed was shown as "Auto", so I assumed it would automatically apply write speed 6x but it didn't. Instead, it was burning at 9-12x. At first it looked OK but at 42% written data, the process got stuck and the writer began making weird sounds. The closest thing to which these sounds were: like a farmer's tractor stuck in the mud and unable to get out, spinning wheels in place. So I had to put in another BD-R disc and manually select writing speed 6x. It surely is slower that way but at least right now it's at 83% data burned and no signs of getting stuck. STEPS TO REPRODUCE 1. Run K3B and insert any 50GB BD-R DL disc in the optical device. 2. Select stuff to burn and leave the speed at "Auto". 3. Start the burning process. OBSERVED RESULT During the burning process observe the writing speed which could vary but will always be higher than 6x. EXPECTED RESULT Inserting a 50GB BD-R disc should automatically select write speed 6x. (see "additional information") SOFTWARE/OS VERSIONS Linux/Desktop: Arch Linux 6.2.2-arch1-1/Cinnamon 5.6.7 Qt Version: qt5-base 5.15.8+kde+r182-1 & qt6-base 6.4.2-1 ADDITIONAL INFORMATION I've bought many dual layer BD-R discs over the last few years and on ALL of them it always reads "write speed 6x" which makes me think this is some kind of a standard, which is why I think the burning software should always select write speed 6x, whenever it detects the BD-R disc is 50GB DL.