USB issues

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Level 1

34 points

USB issues

I've had a couple of instances of Finder not responding - not showing up in a "save as" dialog and disks being unejectable - that seem to be related to USB connections. Once this happens, even rebooting the machine doesn't work - you need to do a full PMI reset (by unplugging everything from the back, including the power cord).

This seems to occur when I'm using a powered USB hub (Belkin) or if my Garmin Edge has trouble uploading data.

Anyone else experiencing issues? Is there an issue with iMac USB ports, or would the hub be behind the problems?

24" iMac (mid 2009)

Posted on Nov 6, 2009 12:45 PM

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Answer 1

den.thed

Level 9

77,158 points

Nov 6, 2009 1:06 PM in response to DanHontz

Hi Dan

I don't have any experience with the Garmin Edge, but it sounds like the iMac's USB bus was or is overloading and tripping the port overload protection.

A few question if you don't mind.....

1. Is that Belkin hub self-powered (having it's own power supply) or bus powered?

2. What happens when you connect the edge directly to a USB port on the back of the iMac?

3. How many other USB devices are connected to the iMac and briefly in what configuration?

Also note: that instead PMI or SMU the correct SMC reset process for an Intel iMac is as follows:
http://support.apple.com/kb/HT1543

Dennis

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Answer 2

DanHontz Author

Level 1

34 points

Nov 6, 2009 1:55 PM in response to den.thed

Hi Dennis, thanks for your time. here are my answers:

1. It's a Belkin 7-port hub that is powered.
2. The Edge did crash the Mac when plugged directly into a USB port, once. But that hasn't happened in quite a while now. And I believe that the one time it did happen the hub was plugged into one of the other ports.
3. Varies. One port is continually used for the keyboard (I use a bluetooth mouse). I also have a m-audio keyboard always plugged in but turned off most the time. Two other ports have my iPhone and my Garmin cables plugged in, but the iPhone and Garmin themselves aren't attached all the time.

Additionally, I have two LaCie drives daisy-chained on the Firewire 800 port.

I've since unplugged the hub to see if things stabilize, but when I did have it hooked up, I just moved the Garmin and iphone cables over to it, and used it for thumbdrives and flash cards as well. I didn't really increase the number of things plugged in, just moved them to a more accessible place.

One thing I'd noticed is that flash storage plugged into the hub often gets "lost" - either a thumbdrive wouldn't mount, or a flash card that was already mounted (in a USB reader) couldn't be ejected. Possibly related is that the Finder has also hung trying to empty the trash -- although that is fixed by a simple restart.

Actually I have been following the SMC reset procedure below. When this problem arises, the Mac hangs on startup (the "spinner" on the gray screen freezes) and the only way to restart the machine is to do the unplug-everything routine described in that support doc.

Thanks again for you help!

-d

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Answer 3

den.thed

Level 9

77,158 points

Nov 6, 2009 2:45 PM in response to DanHontz

I think your doing the right thing by using a hub for carrying part of the load and accessibility. If that Belkin hub is a 2.0 Mac OS X compatible hub then by all means you should be fine using it. Just check to make sure that all of the hubs Power and USB connections are tight.

I've used a [myessentials by Belkin|http://www.microcenter.com/single product_results.phtml?productid=0236737] for almost 3 years and leave my iPod and 3 different camera cables connected to the 4 ports on the back and use the top 2 and front 1 for my portable HD, flash drives and card reader.

The two FireWire drive should not be an issue.

For getting lost, again check all the connections the hub may have lost power or a good connection with the iMac.

For your Startup issue you might want to check: System Preferences > Startup Disk and make sure that Mac OS X 10.6.1 on Macintosh HD is selected, you should not have to reset the SMC to get it up and running again.

The crashing the Finder sounds more like a compatibility issue, head over to [Garmin Support|http://www.garmin.com/garmin/cms/site/us/support] and poke around for an update or contact support.

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