A number of users have found that their multitouch trackpads on MacBook and MacBook Pro computers may randomly stop accepting 3 and 4 finger gestures. While two-finger scrolling, tapping, and clicking will work as expected, the more complex inputs do not seem to be recognized.
This problem could be from a number of factors, including faulty preference files and other system settings and driver conflicts. Here are some tips and information that may help to tackle odd trackpad problems.
Inherent trackpad delays
If there are multiple confusing inputs being presented to the trackpad, the system may pause input for a second or two while it waits for a clear gesture to be used. These delays may be more prominent for multiple-touch gestures, so if you experience them, wait a few seconds and try the trackpad again with a firm and clear swipe instead of frantically trying to get the trackpad to work.
Test the trackpad
The utility "BetterTouchTool" (available here) has a "Live View" feature that can be used to visualize trackpad inputs. After installing and launching the preferences (from the BetterTouchTool menu extra), if the trackpad driver is recognizing multiple inputs you should see the dots representing those inputs on the Live View display. Keep in mind the BetterTouchTool is very experimental at this point, and while it does work it may crash; however, this feature should let you know whether or not the trackpad and driver are still working.
Change trackpad settings
If the trackpad is not loading settings properly, try toggling some settings in the "Trackpad" system preferences. This should spur the system to load the new settings and hopefully get the trackpad working again.
Remove third-party drivers
If you have other input drivers, such as USB Overdrive, Logitech Control Center, or enhancers such as jiTouch or Multiclutch, try removing them and restarting the computer. Many times incompatibilities between input drivers may cause problems.
Try removing the .GlobalPreferences.USER-UUID.plist file
The user account's .GlobalPreferences file is a hidden preference file used for device settings such as colorsync profiles, default printers and monitors, and trackpad settings. After deleting this file and logging out and back in, you may need to ensure these items are setup correctly again. To do this, open the Terminal and follow these steps:
Type the following command (do not press enter)
Press the Tab key twice, and you should see an output of the files containing ".GlobalPreferences" in their name.
Locate the one with the UUID in it (the UUID will look something like this: 6F77B0D6-8208-4977-8B45-EB1ADF6714BA) and start entering part of the UUID portion into the terminal so the command looks like the following:
When you have entered part of the UUID section of the file name, press the Tab key once and the file name should automatically complete, so the command looks something like the following:
After the full filename has been typed, press enter to remove the preference file, and then log out and log back in to your user account.
Reset the PRAM
The system's PRAM contains a number of settings, including those for mouse and trackpad input. Resetting the PRAM should clear any problematic settings that may interfere with the trackpad. To do this, reboot the system and immediately hold down the options-command-P-R keys. Hold the keys until the system resets a couple of times, and then release them and allow it to boot normally.