Safe to plug & unplug Arduino USB cable with PC running?

A while back I had a problem with the Arduino environment reporting a dropped COM3 port on win7 pro 64 bit. After a few days of suffering, I finally solved this by turning off the PC, unplugging it, waiting a minute, then plugging it back in again.

Today, the same thing happened again (and I solved it the same way). It seems like it happened (with the PC running normally) just as I plugged the USB cable into the Arduino.

Is it unsafe to plug and unplug the Arduino USB cable while the PC is running?

I do it all the time. My board still works. Sometimes it takes a while for the computer to connect to the arduino.

I don't think it's unsafe.

Yeah, it's safe. I think everyone here connects and disconnects Arduino boards to USB while the computer is on.

Depending on system conditions, windows version, the specific USB adapter, the chipset in your motherboard, and/or the phase of the moon, windows will sometimes decide to stop recognizing a specific device in a specific usb port until it's restarted. As far as I know, this is a windows bug. Doing things that make it disappear uncleanly (like unplugging it while running) seem to trigger it more, as does shorting out the Arduino (on some systems, this will lock out the port until a full reboot, on other systems it comes back after the short is removed).