Absolutely none at all
Every single one including some pretty old well played ones.
Only "issue" was about 4 cds of very old and obscure British issue nature did not get correct metadata.
Easily and quickly fixed by accessing the vault hard drive from my pc and using mp3tag to fix.
That's it, takes about 7 minutes average to rip a CD to flac or wav files.
For my requirements it was the best solution and the sq via coax digital output with a Nordost silver shadow cable is better than the original CD.
I can give the unit a solid 100% recommendation.