Very Senior Member
Thank you for your reply.
The USB disc has a separate power supply. Sorry I wasn't clear. It just seems odd I can read from it through windows & mac as a mapped drive, just have no write access to it.
Thank you for the AP link. That is pretty much what I have done.
I assume you have verified permissions under the SAMBA settings on the router as per image below.
If so - sorry can't help.