Installing Sims 4 on a new computer

I have been playing for over 3 years on the same computer. I have Drive C as a SSD for program files and Drive D a hard drive for data, Documents etc. Sims 4 has been quite happy with this and saves to Drive D where all my mods etc are.

Have just spend many hours downloading the base game and 65 additions to the C drive on my new computer and set up a Documents folder in the Drive D. I put all my saves, mods etc into it copied from the old computer.

Sims 4 will not access the D drive and just acts as the base game. It has created a new Documents folder on the C drive, where it saves a new household,

Anyone know how to get the game to access the D drive?