My Passport Ultra - 1 TB

Thank you for the link.

When I Enter Time Machine the pink tick marks down the right hand side of the screen are bright pink with within seconds they appear dimmed. The link you sent me indicates that this means " there’s no backup available or the backup disk is not connected "

To me it seems to be backing up okay as all the dates are down the right hand side of the screen but I can’t recover the information -  what do you suggest ?