Windows 8 doesn't detect my MacBook Pro trackpad
Update: Installing Boot Camp 4.0 drivers fixes a lot of problems.
- Open Device Manager. This is found in the Windows 8Start menu by typing "Device", selecting "Settings", and clicking Device Manager.
- Uninstall the drivers for both unrecognized entries.
- Use generic USB Input Devices for both entries. This will allow the trackpad to move the cursor and left click.
- Right click each generic USB input device and choose to update by searching the Internet automatically. Do this until both the trackpad and the multitouch devices are updated.
- Enable right-clicking by opening the Boot Camp Control Panel, selecting the Trackpad tab, and checking Secondary Click in the Two Fingers pane.
Works for me!
Go to Device Manager and uninstall (and delete drivers) for the two Trackpad devices then rescan for hardware.
After which, then go find your Boot Camp drivers, and don't run the full setup, but instead find the folder that specifically has the driver install packages in them and install the ones that are along the lines of "Apple Multitouch Trackpad."
After this, go to your Boot Camp options to make sure that it now sees your Trackpad.
Credit - Microsoft Answers