Resolved External disk & sleep mode

[soloer]

Wondering if anyone else has seen an issue like this. My iMac is working fine since the Lion upgrade while I'm actively using it. However, I've noticed when it goes to sleep mode, my time machine external disk is spinning up and down constantly. It drove me nuts and I finally had to eject and power down the drive to stop it. I haven't seen other reports of this, but I would imagine if it's a bug, someone else has to have run across it.

 

[Partron22]

My external drives did that in Snow Leopard. It seems to have stopped in Lion.
Never did figure out what was causing it.

 

[soloer]

FYI for people that may run into this while using Google..

I found in the Console that a USB device was causing the computer to keep waking up. It seemed to be my Garmin, which has acted weird for quite some time (ie, powers itself on randomly without touching it). I disconnected it and all seems well.

 

[tom5304]

Thank you OP for coming back on and letting us know how you resolved the problem.

 

[lightseeker]

External Disks repeatedly keep spinning up in sleep mode

I have the same problem which started yesterday. 2011 iMac with Lion, one firewire external drive and one USB external drive, both keep constantly restarting and shutting down every few seconds immediately after I have put the Mac into sleep mode. Wasn't a problem last week but now it is - only completely powering down the iMac stops the problem. Have tested changing the energy settings, toggling put the hard disks to sleep on and off but no difference. A solution would be very welcome!

 

[lightseeker]

External Disks repeatedly keep spinning up in sleep mode

After a lot of investigation I tracked it down to the powered USB hub. Although no EHDs are connected to this, unplugging and re-plugging the hub from the iMac USB port fixed the problem.