Did a long-put-off update on my Thinkpad with all its recommended Lenovo drivers from the ThinkVantage tool. All dandy, apart from the fingerprint reader stopped working. It used to have a little green light on to show it was ready, now it was off in sleep mode.
Simple solution: Go to Device Manager > Biometric Devices > TouchChip Fingerprint Coprocessor > Properties > Power Management and untick the "Allow the computer to turn off this device" option.
If I helped you out today, you can buy me a beer below. Cheers!