Rekordbox 6 stuck on "Reading Tracks"

Rekordbox 6 had been working fine but all of a sudden it practically fails to load and is stuck on "Reading Tracks". The library is on an external hard drive which is well and truly accessible from the explorer on both Windows and Mac. The issue persists on both Windows and Mac which I had been using in the past without any problems. Win 10 and Mac Catalina.