Surprising Discovery of "Corrupt" Music Files

When I first started with digital music in 2011, I bought an HDX and used it to rip 1,500+ CDs to .wav format.

I liked the convenience of the HDX, and playback sounded great, but I soon realised the shortcomings of .wav files and the proprietary way that the HDX tagged them.  They were playable on Sonos etc (which I was using in secondary locations) but I had to apply tagging that Sonos could read, which was very tedious.

Also, I was looking for multi-room lossless playback, preferably in hi-def.  I found myself using Sonos into a DAC, to the exclusion of the HDX which I eventually sold.  More recently I have switched to Simple Audio which, while not as user-friendly as Sonos (and it will not be improved following the demise of the company), sounds better and also does anything up to 24/192.

Initially I had a problem with Simple Audio - pops and clicks between tracks.  I found that I only had this problem with .wav files and, indeed, only with .wav files ripped on the HDX.  It was not a problem with anything in .flac, or with .wav files that I had downloaded. 

Recently I used dBpoweramp to convert all my .wav files to .flac.  Having does so, I thought I would do something that I had never done before, and use Perfect Tunes Accuraterip to check the accuracy of my rips. 

I was very surprised to see that, according to Perfect Tunes, quite a large number of albums - some 400 out of a total of about 1,500 - had ripping errors.  These were albums with "ripping errors" per se, rather than albums (of which there were quite a few) that were not in the Accuraterip database, or could not be checked for some other reason.  These were also albums that I had ripped with the HDX, whose selling-point had been very high ripping accuracy.

Having said this, all the albums with errors had played and sounded fine, so maybe the so-called errors were very minor or nothing at all.

I ripped a lot of the CDs again, using a laptop and dBpoweramp and taking the opportunity to add and correct metadata (only basic stuff had come across when I converted from .wav to .flac).  All seemed OK.  I was able to get an accurate result for most CDs, and a secure result for most of the rest, and there was just a small pile of CDs that seemed inherently error-prone.  The re-ripped CDs sounded no better nor worse than before, so perhaps it had all been a waste of time, except for the improvements in metadata.  For the error-prone CDs I just re-instated the previous rip and they also sounded as good as ever.  

Now for another surprise.  I ran the Perfect Tunes analysis again, and this time I seemed to have got rid of the ripping errors but I now had a lot of "corrupted" tracks that I had not had before.  Some of these were CD's that I had just re-ripped (accurately, according to dBpoweramp) and others were albums that I had downloaded, or vinyl that I had converted with Audacity.  Previously (before I started re-ripping) I had not had any corrupted files at all in the Perfect Tunes results.

Nevertheless, the so-called "corrupted" files still play and sound as good as ever.

What's going on?  Hopefully it's all an aberration and my music files were good from day one, and still are.