But how to change if VirtualBox is only running in my computer with kernel 15.6 and I need it for everyday work? 
Ok, I did it! I run Manjaro with kernel 5.17, uninstalled VirtualBox, installed it again… and now it’s working with kernel 5.17!! I never had to do this before, and I hope I won’t have to repeat it in the future 
I’ll keep an eye in Strawberry next days, and if there’s no bug I’ll mark this post as solved.
Thank you everybody!! 
Probably when 5.18 is out 
I’ve been moving at least from 5.10 to 5.17 and it was the first time I had that problem with VirtualBox, so I hope when it comes to 5.18 it will do fine again 
