Thumbthing's wrong with my iMac's USB ports
January 3, 2007 1:28 PM   Subscribe

OSXFilter: Because AskMeFi is where all the coolest Mac nerds hang... On my iMac 24", USB thumb drives and memory cards are failing when copying files. The specific symptom is that the file transfer will hang, and the only way to recover is to manually remove the device from the port.

This happens regardless of whether the device is plugged into the back of the iMac, or into a powered hub.

And, to make the issue extra-difficult to diagnose, it doesn't happen all the time.

Behavior replicates across two different user accounts on the machine, so it's not specific to one login.

Is there some kind of diagnostic tool to run or a driver I can replace? Apple's hardware disagnostic disc comes up problem-free.

And, yes, I've tested the USB devices on other Macs and they work fine.

Thanks in advance, hive mind.
posted by baltimore to Computers & Internet (15 answers total)
Have you repaired permissions? Sometimes relevant system files can have botched permissions, leading to odd behavior. Worth a shot if you haven't tried it.
posted by al_fresco at 1:34 PM on January 3, 2007

Repair permissions, reset PRAM, remove all USB devices one by one to see if there is a conflict somewhere.

I also superstitiously believe that USB flash devices should be connected directly rather than through a USB hub (even the one that Apple provides on the keyboard). I have only anecdotal evidence to support this theory.
posted by crazyray at 1:39 PM on January 3, 2007

It could be the thumb drive hardware or it could be the USB port on you computer IF the file permission fix doesn't work.

Try using the thumb drive on another machine, not just different user accounts.

Does that USB port work with a mouse or a keyboard or other USB peripheral devices?
posted by YoBananaBoy at 1:41 PM on January 3, 2007

Response by poster: Thanks for the advice.

I have tried the thumb drives on multiple Macs, and all work fine except on this particular Mac.

Repairing the perms is something I always manage to forget to do. I'll give it a try this evening.

@crazyray - I'm having the issue with or without the hub (and I've even tested two different hubs) so I don't think that's it.
posted by baltimore at 1:57 PM on January 3, 2007

Response by poster: @ YoBananaBoy - the port works with all devices, and then it doesn't.

For instance, copying a 100 meg folder, it'll move 40 megs or so at the normal speed, then stop dead.

Printer seems to work fine. No interruptions. (I've also disconnected the printer during debugging of this problem, as it's an older 1.1 USB connection and I wanted to be sure that wasn't causing hiccups)

Keyboard and mouse are connected and working fine.
posted by baltimore at 2:00 PM on January 3, 2007

Have you ever installed any "odd" USB device in the past that required a special driver? Perhaps the bad driver is interfering. Definitely pull out any other USB devices you can before testing.

Open up the Console app (in /Applications/Utilities) and look at the console.log and system.log to see if there's any clues as to why it's failing.
posted by todbot at 2:17 PM on January 3, 2007

Interesting - my mini does exactly the same thing occasionally via a multi-card reader. It only seems to fail when uploading a large batch of files (e.g. music) and is irrespective of the type of card - SD, XD, CF - or whether it's a fast, high-quality card, or a cheapie. The cards have either been formatted on a camera (Canon or Fuji), or on a phone (S-E), so I suspect that it's not got anything to do with that.
All the other USB devices on the chain continue to work too, it's just the reader which appears to vanish (the power light goes off, and it isn't recognised unless I physically disconnect and reconncet the reader to a complaining OSX!)

I've never had the same thing happen transferring images to the computer from the card, but I suspect that this is because each image is transferred individually, rather than as one big batch.

I always thought that it was a hiccup with my pretty cheap reader (unpowered, unbranded, 9-in-1) but perhaps it's actually something wih MacOS? It seems to happen from Finder and iTunes (6), and if memory serves, a script called "iTunes my walkman" (or something) also fails which now strikes me as odd, as I'm sure it uploads each track individually...

I know that this doesn't solve your problem, but I think that it may help point the finger of suspicion in a different direction to some of the other suggestions so far...
posted by Chunder at 2:42 PM on January 3, 2007

These files you're copying, are there thousands of little files in one folder? I've had a problem where copying lots of files at once would cause a hang. I found the using Terminal and doing a cp command would work instead of drag and drop in the Finder. I think somewhere around 2000 files is where Finder starts to choke.
posted by Cog at 4:05 PM on January 3, 2007

One thing that I've noticed on my MBP is that the voltage supplied to the USB ports differs AND fluctuates. Perhaps it's a power issue?
posted by aberrant at 4:11 PM on January 3, 2007

You seem to have covered all the normal trial and error tests I would do so it sounds like a software problem more than a hardware problem. You might want to try a finder replacement or trying command line copies. Also, if you have any extensions or unusual background processes, kill them before copying.
posted by chairface at 4:51 PM on January 3, 2007

Response by poster: I'm beginning to think it may just be a bum USB bus. Are there any utilities (other than Apple's Hardware Test) to test USB performance?

Since my first post, and based on the suggestions offered here, I've verified:
  1. Repairing Perms has no effect
  2. Zapping PRAM has no effect
  3. Starting in safe mode has no effect
  4. Creating a new user account has no effect
In all cases, I'm testing this with a 244 MB single file, attempting to copy it to the the desktop folder (before I started trying to isolate this through testing, I had seen the same error with multiple small files as well.)

Most times, the file stops copying at some point (though rarely at the same point). Occasionally (say every fourth try) it will copy successfully.

When it fails, the system log notes this:
Jan 3 20:24:56 marina-windsors-imac-g5 kernel[0]: USBF: 171. 37 AppleUSBEHCI[0x3fa9000]::Found a transaction past the completion deadline on bus 253, timing out!
It sure feels like a hardware glitch.
posted by baltimore at 5:53 PM on January 3, 2007

It's a hardware glitch.
posted by majick at 7:30 PM on January 3, 2007

One last thing to try is booting from an external source (CD/DVD/Firewire drive) to rule out an OS issue.
posted by pmbuko at 7:40 PM on January 3, 2007

I'm voting for hardware glitch as well, but if you want to run one more test before you start complaining to Apple (and maybe you have already tried this) ... have you tried connecting the thumb drive to the computer via a powered USB hub?

This is just a theory, but I wonder if it's somehow power related; perhaps the computer is undersupplying the card during sustained read operations, and this is causing data to be lost during the transfer. Using a powered hub in between the computer and the card ought to eliminate the computer as a source of power problems.

Basically, by using a powered hub, you separate the +5VDC from the signal. If you still get an error, then you know the problem is logical and not power-related.
posted by Kadin2048 at 9:45 PM on January 3, 2007

Best answer: This answer's for the Google cache, as this question is now the number one result for "imac usb fail".

And it's the answer that will thrill the hearts of every First Level Mac Support person out there.

I reinstalled the system software. And it's fine.

After months of avoiding that particular Mac whenever I had a file on a thumb drive, it was as simple as kicking off a reinstall and letting it run whilst watching the latest American Idol in the basement. I came back, and all was just dandy with the USB bus.

So color me a bit embarrassed for not trying the number one most popular solution after "is the computer plugged in?"

There you go, Google cache. Another Mac support mystery solved.
posted by baltimore at 7:19 PM on March 6, 2007

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