External hard-drive does not reconnect after sleep

Please give us the specifics about your USB external hard drive.

Also, if you manually put your computer to sleep, does the hard drive reconnect upon wakening as it should? And what happens when the hard drive is connected directly to the computer rather than through the hub. I know I have one USB hard drive that simply doesn't work through my Hub.

Good luck.

Arch

r_dizzle wrote:
Another point of note is that both the HD and the keyboard are connected to the iMac through a 7 port USB hub.

I think this might be the issue. If the iMac is waking back up, it will likely be waking up this HUB, but the HUB might not be re-initialising the connection between OS X and the external drive or the keyboard.

After waking the iMac, if you unplug the external drive from the HUB, then plug it back in again, does OS X pick it up again? Have you tried plugging the external drive directly into the iMac and then testing what the result is?

If you read back on what you've said, you pointed out that you have a USB mouse that you use to wake the iMac from sleep. Is this mouse directly connected to the iMac? If so, it surely can't be a coincidence that a directly connected USB device can wake the iMac from sleep, but any USB devices connected to the iMac via a USB HUB cannot.

I would suggest you test the drive as it is directly connected to the iMac. I would complete the same test with the keyboard too. I think you'll find it's the USB HUB.

I hope this helps.

I have an identical issue to the original post. External hard drive and external keyboard/mouse connected to a hub. The added info is that when I wake the laptop sometimes but not always there's an error message saying an external device was improperly disconnected. When I see that the external mouse and keyboard are dead. However the trackpad and keys on the laptop still work ok. I found by trying to diagnose the mouse issue that if I unplug are replug in the USB cable every time then works OK. Also once that's done sometimes the external drive remounts while other times I have to restart to get it back. The external drive is my Time Machine target so sometimes I get a 'backup failed' error, but not when the wake up error occurs. Directly connecting to the laptop usb ports is problematic because the MacBook Pro only has two, and to directly connect the keyboard/mouse combo and the hard drive and the hub takes three.

David saved me a lot of typing. I am having the identical issue with my MacBook Pro (2.53 i5). Using a Kensington 7 port USB Hub, a stock Mac keyboard, and a 1TB Western Digital My Book.

Some third-party devices don't support sleep properly on the Mac, and either never go to sleep, or don't wake up when they should. It's really up to the peripheral manufacturer to fix it.