My existing back up external WD hard drive is connected to my IMac running Mountain Lion but is now full. I have purchased another and wish to piggy back it to the original. Just cannot see how to do it. Do I need a split USB to mini USB lead. Help please but please try not to get too technical at 76 my brain is not so receptive as it was!!!
Certain drives do not support this feature.
What model drive do you have?
The drive is MY Book for Mac 2TB and the model number WDBAAG0020H-02.
I have just noticed that it is formatted for OS X snow leopard whilst I have Mountain Lion OS X 10.8.3 Does that mean it will not work anyway?
The drive is fully compatible with your OS.
Connecting multiple drives on Mac is regularly done via Daisy Chain.
This feature is supported on WD drives that have Firewire connectors. Please see the link bellow for more information:
http://wdc.custhelp.com/app/answers/detail/a_id/561
http://wdc.custhelp.com/app/answers/detail/a_id/1490
With the setup you have, we support connecting both drives to the Mac in separate ports. You can use one of your drives for backup and the other one for your old data storage.