Stopping USB drives from starting unnecessarily

[MulgaBill]

I have 2 external USB drives attached to my iMac that I use for backup. When ever I start or logon the drives both start even though they are not required. This is also true when ever I start other applications

Is it possible to change a setting so that the drives only start when required. i.e. during backup?

[smithrh]

I have 2 external USB drives attached to my iMac that I use for backup. When ever I start or logon the drives both start even though they are not required. This is also true when ever I start other applications

Is it possible to change a setting so that the drives only start when required. i.e. during backup?

Yes, use Disk Utility and unmount them. You'll have to re-mount them in Disk Utility when you want to use them.

To my surprise, the mounted/unmounted state was kept over a reboot cycle, which is great. I'm not sure that ejecting them from the Finder has the same effect.

The other alternative is to eject them and then physically un-plug the USB cable until you want to use them, then re-connect them.