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I have 4 USB ports on the front of my computer and 6 in the back.

I have about 8 USB devices: external drives, sticks, cell phones, cameras.

It is often the case (40% of the time) that I plug something in (usually the external hard drive or cell phone) and it is not recognized or doesn't work correctly. My solution is to just plug it into another USB port (usually switching back-to-front or front-to-back works). I've found that this solves the problem 100% of the time.

Am I doing something wrong or is there just something "not quite baked" with USB (2.0) technology? It seems that e.g. the external hard drive "tires of its USB port" after while and needs a new one to be recognized again, i.e. there seems to be some kind of caching or ID recording that is going on.

This has happened on the last two computers that I had and still on the new one I just bought. The last two computers have USB 2.0 ports.

Can anyone explain what is going on with USB that would cause this phenomenon and perhaps what I could do so I dont' have to keep unplugging and replugging my USB devices to get them to work?

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"not quite baked" is right. dunno that we can properly assign blame, tho. is it the OS? drivers? chipset? (which? bus chipset, or device chipset?) or the USB spec itself? i blame Cheap Plastic Cr*p(tm). –  quack quixote Nov 11 '09 at 7:26
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Easier to answer it you stated your OS, Edward. –  CarlF Nov 11 '09 at 7:56
    
I have had a similar experience as Gerd below. I have a brother P-Touch label printer that works only the port I used to originally installed it on. This is very sloppy driver development. The device independence principal was established decades ago. –  Kije Nov 11 '09 at 13:05
    
@CarlF my last three computers have had: Windows XP (SP1/SP2/SP3), Vista, and now Windows 7 and this has pretty much happened consistently on all of them –  Edward Tanguay Nov 11 '09 at 23:03
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2 Answers

up vote 10 down vote accepted

I suspect you are having power problems. With that many USB devices, some hubs can be overloaded and won't enumerate correctly. Moving to another port probably moves it to another hub which has sufficient power. The solution I have found when I've had these problems is to go get a powered external hub and plug into that. That has solved my enumeration problems every time so far.

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Some drivers and applications cache port infos and try to access the USB resource always in that location.

That is definitely the case with my UMTS mobile USB stick. The port I used the first time is now the only one that works.

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