To convert files back to (or other original formats like BIN/CUE), you need the official MAME utility called
The standard tool for decades has been the MAME toolset (chdman.exe). The classic command is: convert chd to iso better
Best method overall: chdman in command line. It’s faster, safer, and batch-friendly. GUI tools are fine for one-off conversions if you fear the terminal. To convert files back to (or other original