Hi,
I regularly get this error while trying to rip a CD, which sometimes solves by itself, sometimes not.
when it does not I need to rip the CD via Windowsmedia player (usually cannot rip when musicbee had the message, or VLC which rips almost everything but without anydata ( lots of effort with mp3tag afterwards..)
here is the text
MusicBee v3.3.6904.36051 (Win10.0), 13 nov. 2019 15:46:
System.NullReferenceException: La référence d'objet n'est pas définie à une instance d'un objet.
à #=zz0Bq7BLGOEkHxh7_2U1TDpIE38Kr.#=zMxfTqc_IdzwjW5N68Q==()
à #=zz0Bq7BLGOEkHxh7_2U1TDpIE38Kr.#=qhF1CyT_bZThTMOM91copj5v1Xh2ORaNyS_4MHtCbatg=._Lambda$__0()
Hope this helps