Are you aware that Mozart 225 splits into 29 “Mini” volumes which are ID’ed automatically by Roon and then navigate easily , the biggest is around 20 CDs
This box was discussed in a thread on Search just after the transition of search to the cloud. It was identified as a very difficult set to search simply because of its size. I’ll see if I an find the thread if it helps.
I stopped trying very big boxes in Roon for this reason, this is how it looks in JRMC
Anything over say 50 CD’s is simply too big to be usable in Roon
