Apple has recalled the iMac  to replace the potentially  defective Seagate hard disc. It is prone to crashing.

The last 24 hours have been spent backing up all the files on the hard disc of the 27 inch iMac to the NetGear Nas Raid storage device,  and then, to make doubly sure,  backing the digital and film files to the portable Lacie hard discs.

It has been a nonstop backup. As soon as one finishes I start another.