This didn't work for me on Thinkpad yoga 12.5 - but a lot of people seem to have these issues on all brands with Synaptics drivers.
Tested with removing the actual cable to the trackpad, rebooting -> shutdown, reconnect and boot again -> same issue.
Ultimate solution was to manually update the driver (HAVE DISK method) after downloading and expanding the Thinkpad UltraNAV drivers (in win8.1 -> it will not allow you to just install the Synatic Driver as it's not digitally signed, while I'm sure there's a workaround it's too much work).
Download and install UltraNAV driver from Lenvo (for your OS version) and it will autoexpand (from the installer) to:
C:\drivers\WIN\UNAV\WinWDF\
Before letting the second part of the full UltraNAV install complete (which will fail as it will not find the driver for the touchpad), you will need to go to Device Manager (in win8 -> WinKey+X, then Device Manager), Expand the "Mice and Other Pointing Devices":
If you show an entry for PS2 mouse instead of your trackpad -> Right Click on the PS2 Mouse -> Update Driver Software -> Select Browse My Computer for Driver Software -> SELECT "Let me Pick From a List of Device Drivers" -> HAVE DISK and Browse to the file (or folder) C:\drivers\WIN\UNAV\WinWDF\x64\synpd.inf (or x86 - depending on your need) and select OK.
This method will force the OS to recognize the trackpad (every other method I tried failed - Admin of 12 yrs... it should never be this difficult - this is how you install beta drivers on beta hardware or in this case get around a driver conflict).
Hope this helps.