AI, which is not guaranteed 100% accurate, offers this...
"Express Burn lacks true multisession support for video or data Blu-ray discs and is limited to appending tracks only in certain audio CD scenarios, not for mp4 video files or data discs.
If the goal is to continue appending files to the disc without ever erasing its original content, consider this...
Alternative to Express Burn
- Windows Explorer (UDF Format): Windows 11/10 can format rewritable discs (BD-RE) as a "Live File System" (UDF), allowing users to drag and drop files in multiple sessions without erasing prior content. Insert the BD-RE, format it as a live file system, and add files as needed. This method is suitable for general data archiving, but compatibility may vary on hardware players.
- Recommended Practice: For best results and highest compatibility with 4K/Blu-ray players, collect all files to be burned and finalize the disc in a single session."