upgrade from 19 to 20 ?

I have a project in DR19 stored on an SSD. Project file .drp etc also stored on SSD. I then plug this ssd into my MAC with DR20 beta1 and import the project which works fine except that all the bins are now empty. All clips are stored in the same place on the SSD so it should just be a matter of relinkeing them... shouldn't it? ... or am I missing something.

From this it seems that exporting the project doesn't include links to the bins and all the clips in them otherwise thye should show up in the bins allbeit in red.

Grateful for any assistance in solving this