Many manufacturers finally developed working solutions for automatic driver updates distribution for their gadgets. For instance, Samsung recently released a new driver for USB host controller in their notebooks.
Too bad if you haven’t disconnected your USB HDD while the driver update took place, your external drive most probably has lost all its files.
Well, you can still try to restore files from the drive. The USB controller driver update zaps MFT table on the disk, leaving the files themselves intact.
You may try to recover lost data with R-Studio, which is one of the best drive restoration utilities.