CanoScan LiDE 200 on Mountain Lion: Failed to open a Session on the Device because it (the Device) was Locked!
Just a very quick tech note for the Community, since it took me way too long to solve this problem: assuming you have updated your drivers and so on, if your CanoScan LiDE 200 (or similar Canon scanner) still gets you an error in Image Capture on a Mac, the scanner might be locked.
The lock switch is on the bottom of the scanner.
I had by then already updated the drivers, but I probably didn’t need to. Unlock; unplug; re-plug; re-launch Image Capture; voila. It took a while to warm up, but then it had been in storage for two years (which is of course why it was locked).
That did the trick for me. Of course it would have been lovely to have the software say “Your Scanner is Locked, Dumbo!” But I guess it’s a more secure lock if you forget it’s there!