Comentário oficial
To those who have issues after installing rekordbox 4.2.0:
Please download the previous version 4.1.2 from the link below.
For Mac:
https://www.dropbox.com/s/2rkmk3bjwwaj5li/Install_rekordbox_4_1_2_mac.zip?dl=0
For Windows:
https://www.dropbox.com/s/weu4o9pskrb7yc3/Install_rekordbox_4_1_2_win.zip?dl=0
If you still have any issues, please create a ticket from the link below.
https://rekordbox.com/en/support/inquiry.php
Sorry for the inconvenience and thank you very much for your kind cooperation.