Getting "unsupported file format" on some tracks

I’ve noticed recently that sometimes while accessing a track I get “unsupported file format” message and can’t access the track. During a gig, when you get 2 or 3 of these in a row, it can really mess up your flow. THoughts? I’m on RekordBox 6.8

What kind of files are they? I’d check that first and then maybe if they are corrupt