Apple simply doesn’t have a software solution designed specifically for burning and copying BD’s. There is BD support in Final Cut Pro and it works for burning your movie project to BD but there’s no telling how long that will last. Of course all this could be avoided if Apple supported Blu Ray. That is most likely how you will resolve your issue. They should give you detailed instructions in email on how to do a clean uninstall and clean install over the new OS.

Roxio support has a bad reputation but in the end they did finally come through for me. Unfortunately you will either have to rely on tech support from Roxio (open a ticket with them) or down grade your OS back to Mojave. They cannot! They can support only their own software (sometimes imperfectly). Apple does not guarantee all software will be compatible with their OS. This is a major new operating system which is a new generation. Naturally I was concerned that Big Sur would present it’s own set of issues and that is indeed what I’ve been seeing! You are not the only one experiencing issues with program errors (including Toast 19 specifically) after upgrading to Big Sur. Fortunately I can copy the projects I burned to BD-R, DVD-R or CD-R with a functioning Toast. I lost projects which were produced in 32 bit versions and there’s no way to get those back. That was a nightmare to install properly as I kept having issues with it crashing as soon as I would try to use it! Finally a detailed correspondence from Roxio showed me which residual files from my last installation needed to be excavated and removed and after several attempts, I was successful in getting a stable installation for my use. I read the negative reviews about Toast18 Pro but I paid the money and downloaded it anyway. I had zero problems until I upgraded to Catalina and all of my 32 bit applications were rendered useless. It seems the last solid product was Toast 12 which I used for years. The newer management which owns the Toast brand has been under fire for releasing expensive, substandard products. We are on our own with third party software.

Unfortunately, Apple is not likely to see this as their problem and they would be right.

Toast for mac mount disc image