Unplugging USB rebooted my PC....

[michael8554]

Spent this afternoon labeling all my USB plugs and hub sockets, so that they always go back together the same, and clearing out all the "hidden" COM and USB connections that result from different plugging each night.

This involved unplugging everything and then putting back one plug at a time.

However, when I unplugged my YesYes modified webcam (internal USB hub and USB-to-Serial converter), my PC rebooted itself.

As I said, nothing else was connected to the PC at the time, even the 4-port hub it was plugged into at the telescope end of a 5M repeater USB cable was un-powered at the time.

I checked for volts between the shrouds of the camera USB plug and the hub socket but nothing doing.

Any other checks I can make?

Michael

[malc-c]

USB items should be "unloaded"  from the task bar first rather than simply pulled out.

[Cath]

What OS do you use I wonder?

A PC should never reboot just by unplugging a USB device. If it does then it most likely means faulty software/driver. Even you were to short the power pins on the PC's USB socket the PC should not reboot as the USB power is current limited (normally to 100mA).

[Gina]

USB items should be "unloaded"  from the task bar first rather than simply pulled out.

I didn't know that!   I'm always unplugging USB devices and plugging them back in.  I though that was the idea - plug-n-play

[malc-c]

Gina,

Whilst that's possible and we all do it (especially with memory sticks), lock ups or reboots can occur when USB plugs are pulled and the device driver was trying to communicate with the device being removed. 

[Gina]

I see what you mean.

[Dave_D]

check your event viewer to see if there's any big red warnings associated with the device

[Zakalwe]

I didn't know that!   I'm always unplugging USB devices and plugging them back in.  I though that was the idea - plug-n-play

It depends a lot on the device and it's drivers. USB hard drives, for example, will not take being yanked out kindly. USB memory sticks are less likely to fall over, but data held in cache memory on the main PC may not get written back onto the USB stick. These always have to be unmounted before unplugging.

Some device drivers will lock up the port if the device is unplugged. Atik cameras seem to do this, especially if the control program crashes. You then have to reboot the PC or kill the Atik driver in Task manager to get the camera to reconnect. The PC rebooting was likely due to a poorly written device driver.

[Davey-T]

Having scrambled a USB stick once I always click on the "Safe to remove USB" including SDHC camera cards.

Dave

[michaelmorris]

This problem is relatively common.  Philips SPC 900 webcams are notorius for it.

[Gina]

I know to software disconnect HDs and memory devices to make sure there is no data being sent but I often get Atik cameras to recognise the USB device by re-plugging.  Same applies to Arduinos.  Hmm...

[michael8554]

Thanks for all the replies.

michaelmorris says it's not uncommon for Philps webcams, which is a sort of relief.

I always use the "safe to remove" or "eject" option with memory sticks and external harddrives, but there isn't that option with webcams, DSLRs, mouses, USB hubs, and USB-to-serial devices.

Michael

[jarl72]

Has happened to me before, but I think I isolated the problem to static electricity being discharged through the USB plug into the port. Were you working on carpet?

[happy-kat]

Also if the device is a harddrive it won't park the disk unless you stop the USB device I think

[redmoo]

Were you unplugging from the back of the PC or the front? Could it be as simple as an unsecured power connection? When you unplugged the USB, you might of touched the cable, which would result in a reboot when the power came back.

I only suggest this as it is something I myself have done....on several occasions! 

[MontyUK]

Check the connection tab inside the socket.  If that flexes and the live tab touches the shell it may reboot the computer by instantaneously shorting and cutting power.  happened to me once on a very old laptop with a broken tab.

[michael8554]

I unplugged the guidecam from a hub at the far end of a 5M repeater cable.

Momentary short in the socket a distinct possibility, I may have pulled the plug out at an angle....

This was a one-off situation, as my latest plan is to power off with all USB plugs in.

Michael