We have thousands of CDs, and around 12 or 13 years ago, I began backing up all of them using the XLD program. XLD rips accurately and indicates if any errors occurred in the ripping process.
There have been at least two occasions over the years in which a particular track would not play, and I had to back up the track again to replace the corrupt file.
As XLD provides a readout indicating if any tracks were not properly extracted, I can only assume that these two files became corrupt over the years, after they were accurately ripped.
I realize that two tracks out of thousands of albums is not a big deal in the grand scheme of things, but I wonder if anyone else has experienced this or has any insights. Over the years, I have copied files from one external drive to another. While these should in theory be exact clones, I wonder if the damage occurs during this copying process.
Just one more reminder that no single format is perfect.