How to enable Synaptics Touchpad While Typing (without disabling palmcheck)?

The problem is that Synaptics "palm check" is not your problem. Palm check detects that your hand is resting on the touch pad, and will not intemperate that as an attempt to move the mouse.

The problem is a setting in windows 8 that disables tapping while typing. However the correct driver should automatically disable this, and use palm check only.

Make certain that your driver is in fact up to date. Make sure you get the latest driver from the manufacturer that is intended for your laptop and for Windows 8. If no driver is offered for Win 8 try the Win 7 driver, or the generic driver from http://www.synaptics.com/resources/drivers. Be sure to fully remove your driver before installing another version. If there is no Win 8 OEM driver for your device, and none of the others work either, then you can try disabling the setting manually:

Unfortunately I can not seem to find the location of the setting! It's easily accessed in 8.1: Open the charms menu, select settings > "Change PC Settings" > "PC and Devices" > "Mouse & Touchpad" and disable the taps delay. But I can not locate the same setting (which may have a different name) in normal Windows 8.

If the setting is grayed out (or otherwise impossible to change) then you may need to remove your drivers, disable the setting, then re install them.

If it still doesn't work, then I am afraid you will need to contact your laptops manufacturer for assistance. They may release a new driver in the future, or it may not be possible to fix. In the second case, there may be third party software that can help you.

At least that's how I got it to work when I had a similar problem. Though soon after fixing it a new version of the driver was released that not only would have fixed it, but made it work even better. YMMV

In a similar post - Use touchpad while “typing”? - the following answers were proposed.

Disable/reduce SmartSense

This described in detail in How to Turn PalmCheck On or Off for Touchpad in Windows.

• Open Control Panel -> Mouse
• Click on the TouchPad Settings tab, then on ClickPad Settings.
• Double Click "SmartSense"
• Slide the Slider all the way to "Off"
• Click Close and OK.

The article Prevent Touchpad From Being Disabled by Keypresses says further:

Although it doesn’t mention disabling the touchpad while typing, it in fact does do this while set above 50%.

I recommend setting it to around 50%, or have a play around to find what works best for you. You can test whether the touchpad is still being disabled easily by selecting a new value, then holding the Tab key and attempting to move the touchpad. If the touchpad stops responding after a couple of seconds, the PalmCheck setting is still too high.

Registry update

In the Registry, go to the key HKEY_LOCAL_MACHINE\SOFTWARE\Synaptics\SynTP\Defaults, and set the value of all string entries of the form PalmKms…, to 0. (Of course, they probably don't all need to be 0, but have fun finding out which one(s) you actually need!) These values determine the amount of ms that the touchpad stays disabled after keyboard input has been detected.