Hello @CaseySJ,after a while i tested all usbs connections and i have also changed the usb cables.....in mojave and catalina,and same problem,the system eject hdd ramdomly or when transfer data ,this is crazy ¡¡,so did in the new card pci 3.0 usb¡¡...(
https://www.amazon.es/gp/product/B00HJ1DULE/?tag=tonymacx86c03-21)
What I do not understand,for example today i transfered with carbon copy cloner 500gb from hdd red nas 3gb to hdd red nas 4tb and in the middle i have had error,te system have ejected one drive.And after i have continued the transfer and it has not disconnected...this situation makes me desperate¡¡¡
I don't know if I do something wrong in the installation or I don't know....Remember the same disk in macbook dont have any error.
Before this MB i had z370 aorus gaming 7 with same disk and I didn't have these problems either...
if something similar has happened to someone...
Thanks for listening...
EDIT:Now i have connected only 1 hdd(seagate 2tb external usb 3.0)and after 2 hours its ejected without doing anything....
The other hdd (Western digital nas its not connected)