WD MyBook 4 Terra connected to late 2018 MacBook Pro 15'

I can’t move my files (photos) to folder photo using my new Thunderbolt MacBook Pro 15’ ( Mojave)

While I can do this on my old MacBook Pro ( Sierra)
what do I have to do ?
Any tip ? thanks !

You can try checking the permissions on the drive. whether the drive has full Read and Write permissions on it or not.

You can try reformatting the drive. Follow the link given below:

YES ! it works. (check permissions). Thanks !