Usually when USB devices are plugged in, they will be successfully recognised and installed. Unfortunately, there are those occasions when my wonderfully-archaic computer decides that it doesn't want all these USB devices, and so will simply render all USB storage devices inoperable.

It does this by suddenly forcing them to be "unrecognised"; often leading to data loss and MFT corruption. Other USB devices, such as my headset or USB mouse are unaffected. I have found that I can usually trigger this problem by having at least four devices plugged in - typically mouse, ext. HDD, headset, and then once a flash drive is plugged in both the flash drive and the ext. HDD become unrecognised.

The only possible way I've found of fixing this problem is to load Device Manager using

start devmgmt.msc

setting it to show hidden devices, uninstalling all USB drivers for all previously installed devices and hubs, shutting the computer down, and then unplugging it from the wall overnight. This becomes a very time consuming process for an issue that you would think would be something easy to fix.

I still have free USB ports when the issue occurs, but the fact that it requires leaving the computer unplugged overnight to fix suggests to me that it may be an issue with the BIOS or motherboard itself. How this happens though, I have no idea.

Any suggestions or thoughts to prevent this or alternative suggestions to fix the problem that take less time would be much appreciated.


Are these USB devices self-powered?

If not, it might be that the power-supply is not up to the task of supporting them. As you mention that this is an old computer, I hope that the power-supply is not getting weaker in its dotage.

  • my first thought as well. flash drives, mice, headsets will probably all be bus-powered, but the ext. hdd might not be. it'd be a large drain on the power resources if it is; replacing it with a self-powered ext. hdd would help (assuming this is diagnosed correctly). – quack quixote Dec 11 '09 at 15:51
  • You're correct; none of the devices are self-powered except for the external hard drive. If I recall correctly, however, this issue didn't occur a while ago, and\or I was able to have more USB devices in. I've also seen Windows alert on devices sucking more power than it can supply them with, so wouldn't it alert me to this rather than just cause data corruption? A weakening power supply is another consideration, and I'll pop the case open in the morning and have a look at it to see if I can find anything else out about the PSU. – mechanarchy Dec 11 '09 at 15:55

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