How do I enable "Momentum" (aka "Inertia") on a notebook with an Elan touchpad?

NOTE: This answer is outdated. You don't need to modify the driver configuration file to enable Momentum anymore. You can simply change the relevant DWORD values at the following registry keys to enable/disable Momentum and a host of other features.

To enable Momentum, set Momentum_Enable and Momentum_Display to 1. You can find them in the registry keys listed below.

For Windows 10:

1. Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Elantech\SmartPadDisplay

2. Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Elantech\SmartPad

After doing this, Momentum or 'Inertia' related settings will start showing up in the 'Elan Smart-Pad' application that lets you configure various features of the touchpad.

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I finally figured out how to enable Momentum (called Inertia in Elantech touchpads) as well as a host of other hidden features in ELAN manufactured touchpads.

Thanks to this blog post, I found out that the way to do this was to edit Elantech drivers (ETD.inf). If you're using WHQL inbox drivers, you'll probably have to downgrade to older Elantech drivers for this to work.

Make sure that the touchpad drivers you have include a setup.exe file so you can install the drivers. You'll also have to run Windows in Test Mode with integrity checks disabled so you can install the modded drivers. To restart Windows in Test Mode, run the command prompt as administrator and enter the following commands:

bcdedit -set loadoptions DISABLE_INTEGRITY_CHECKS
bcdedit -set TESTSIGNING ON

Uninstall the previous touchpad drivers and make sure you check the Delete the driver software for this device box

Now open ETD.inf in the Elantech drivers folder with a decent text editor (I recommend Notepad++) and change all instances of

Momentum_Display,%REG_DWORD%,0

to

Momentum_Display,%REG_DWORD%,1

Also change the first instance of (you'll find this in the [ETD_SmartPadUI_Default.AddReg] section)

Momentum_Enable,%REG_DWORD%,0

to

Momentum_Enable,%REG_DWORD%,1

If you'd like the cursor to bounce off of screen edges, then change:

Momentum_Bounce_Enable,%REG_DWORD%,0

to

Momentum_Bounce_Enable,%REG_DWORD%,1

There are lots of other options you can enable/disble as well. However, I'll leave it to you to experiment with them. You'll find the most interesting settings in the following sections:

[ETD_SmartPadDisplay_Default.AddReg]
[ETD_SmartPadDisplay_Win8.AddReg]
[ETD_SmartPadUI_Default.AddReg]

WARNING: Make sure you know exactly what you're doing here or you could end up with an unstable driver and lots of BSODs. I recommend making a backup of the original drivers before you start to modify them.

After you've finished editing the drivers, reboot your computer and install the new modded drivers by running setup.exe

Thanks to the guidance on this forum I was able to enable momentum/inertia on my HP Pavilion X2. It is actually very easy to do (no need to re-install drivers).

1. Windows+R and type in Regedit, hit enter. This opens registry
2. Hit control-f to pull up the search box. Uncheck all options except Values
3. Paste Momentum_Display in the search box and click FIND NEXT
4. It may take a minute to return result, but once found, Double click on the value and (I) Change Base to Decimal (II) Set Value Data to 1
5. Repeat the search until all instances of Momentum_Display have been changed (there can be more than one).
6. Repeat steps 2 to 5 for the following values
   • Momentum_Enable
   • Momentum_Bounce_Enable
7. Press WIN+X>Shut Down or Sign-out>Sign Out.
   • Sign-Out
8. Sign-in again, and move mouse...it should now glide momentously across the screen.