Unable to keep my external hard drive connected to my computer for backup with Time Machine.

I am using an external LaCie hard drive to backup my computer.  In the last month or so I have noticed that when my computer is in the sleep mode for sometime the hard drive disconnects from my computer.  I than get an error message that tells me that I have failed to disconnect the hard drive device before turning it off.  Do I have a problem and if so is there a fix for the problem.


I have a similar question. I have backed up my external hard drive through my computer, onto my TC. When I go into TM, it doesn't show the external hard drive unless it is connected to the computer. Can I access the info from the external hard drive that is on the TC if I don't have the hard drive plugged in? If so, how can I do that?