I am rather late with my answer, but I believe people still come across this problem, so it might be useful. And is there any way to fix it? If yes then how? What can be cause of this? Given that the device is working okay in Ubuntu, I assume that the hardware itself is not damaged.

I read that it might be a driver problem. In addition, I tried to plug this flash drive into freshly installed Windows 7 圆4 Ultimate. FYI the filesystem was NTFS, reformatted as FAT, so that's hardly the issue. However, under Ubuntu 10.04 on my netbook, the flash drive is fully operational: I could easily back up data from it, format it (however formatting did not help to get it running on Windows). Windows 7 also fails to find and install drivers for Unknown Device.The device shows up under Other Devices / Unknown Device and Universal Serial Bus Controllers / Unknows Device in Device Manager.The device is not present in Computer Management / Storage.After that I could not get it working on any of my Windows systems too.

One day I lend it to my friend and when he brought it back, he told me he could not get it working. It was working okay on all my computers, like a flash drive usually does. I have a Corsair Flash Voyager GT with capacity of 16 GB bought roughly 5 years ago.

My pen drive not showing