What are you building in? Which version of Windows is your system running? Share public link
A 32-bit (x86) application is trying to call a 64-bit (x64) ZKFinger DLL, or vice versa.
ZKFinger VX100 (more commonly referred to as the ZKFinger SDK or driver for ZK-series readers like the SLK20R, ZK9500, or ZK4500) is managed through the official ZKTeco ecosystem. Latest Official Downloads
The ZKFinger SDK is not a single file but a comprehensive resource package designed for developers. It provides a programming interface (API) for communication between a PC and a ZKTeco fingerprint sensor. The SDK is a complete toolkit that typically includes several key components:
The USB driver is missing, or the scanner is plugged into a faulty USB port.