Just tried the command line ignoring plug ins ... issue (slow display). No improvement just click hurry up & wait
Am also running Win 20 64 bit (Calibre 64 bit v 5.2). My library is very large but has not increased substantially from that when running 4.x version(s) (no idea why library size might impact display of dialog - just throwing it out there). Library has been checked by Calibre with no errors/anomalies reported)
Was hopeful when i saw your idea but no joy
Thanks for your response
Appreciated