Cannot import photos from iPhone 4S (iOS 9.2.1) into iPhoto '11 (9.4.3)

When iPhone 4S (12.5 GB) is connected by cable to MacBook Air (processor 1.4 GHz Intel Core 2 Duo; memory 2 GB 1067 MHz DDR3) and iPhoto is opened, error message displays: "Photos in the Camera Roll of "iPhone" cannot be imported because the device is locked with a passcode." The iPhone is not locked; does not currently have a passcode enabled.

Tried resetting iPhone settings in case "don't trust" had been selected for the MacBook Air; problem persists.