T450 clickpad (with buttons) in T440 T440s T440p - Unable to connect to the synaptics pointing device driver

If you buy (at ebay or aliexpress) 3-button touchapd from T450 for your T440 / t440s / T440p you can get following error:
"Unable to connect to Synaptics Pointing Device Driver" .

BASIC SOLUTION

• uninstall Synaptic software
• remove "mouse" pointing device
• restart windows
• clean Synaptic registry entries using CCleaner
• restart windows
• install UltraNav[n10gx25w] driver

... usually works.
While not...

ADVANCED SOLUTION

• Go to "Device manager""
• Expand pointing devices
• Click properties
• Go to details tab
• Check Hardware ID
• if there's:

ACPI\VEN_LEN&DEV_0036
ACPI\LEN0036
*LEN0036

it can be used driver for YOGA 15 (http://support.lenovo.com/de/de/downloads/ds101993).
Its ALPS driver so it's obviouse that Synaptic driver don't work :-)


Devices with hardware id: ACPI\VEN_LEN&DEV_0035 worked with Synaptic driver
Inspiration:
http://jonsson.ninja/t450-touchpad-on-t440-upgrade/
http://forum.notebookreview.com/threads/t450-t550-touchpad-on-t440-t540-mod.769254/