| Error Message | Likely Cause | Fix | | :--- | :--- | :--- | | "Installation failed – Write to folder denied" | Windows UAC blocking | Install to C:\Fingerspot (not C:\Program Files ). | | "Database driver not found – 0x80004005" | Missing Microsoft Access Database Engine | Download the 64-bit Access Redistributable from Microsoft. | | "License key invalid" | The software version does not match the hardware generation (e.g., using SF1000 key for Face ID 8). | Contact distributor for the correct key. | | "Device not responding after download" | Firewall blocking port 5000 | Add an inbound rule to Windows Firewall for FingerspotService.exe . | | .NET Framework missing | Windows 11 often lacks legacy 3.5 | Go to Control Panel → Turn Windows Features on/off → Check .NET 3.5. |