Rekordbox locking

Hello,

I would like you to help me in an issue, I own a ddj 400 and a macbook pro mid 2010 with the whole high sierra system updated so the current rekordbox too. The notebook has 4 GB of memory and works very well because I use practically only for the use of rekordbox, so it happens that when playing a song on deck 1 for example and when I will load on deck 2 the music that is playing gives a lock, I already looked on the internet and I was able to find on windows that the same problem happens. How do I solve this issue on the Mac?

I'm waiting, and thank you from now on!

hug