One of my customers reported an unusual problem today with their keyboard, mouse and trackpad. When they tried to to use Apple’s Mail or Messages applications on OS X El Capitan, both Mail and Messages were unresponsive to either keyboard, trackpad or mouse input.
However, when they selected another non-Apple application like Firefox or Google Chrome, their keyboard, trackpad and mouse behaved normally. Other Apple-installed applications like Safari were also responsive to keyboard, trackpad and mouse input.
When I checked the logs, the main clue I could find was that when I clicked on Mail or Messages, I would see an entry like this appear in /var/log/system.log:
09:02:06.100 sandboxd[701]: ([458]) Mail (458) deny hid-control
hid in this instance refers to something which Apple classifies as a Human Interface Device, which include the following devices:
- Keyboards and pointing devices such as mice, trackballs, and joysticks
- Front-panel controls such as knobs, switches, sliders, and buttons (for example, controls on non-Apple displays)
- Controls that might be found on games or simulation devices such as data gloves, throttles, and steering wheels
So for some reason the sandboxd process was denying access to Messages and Mail for the mouse, keyboard and trackpad. Why? For more details, please see below the jump.
After some additional digging, I found an Apple discussion forums thread that explained the issue. If a graphics tablet has ever been connected, or if third-party software has been installed to allow a trackpad to emulate a tablet, the Mac may only be allowing input from that tablet for the affected applications.
The affected customer in this case was using a Wacom tablet and had hard powered-off their Mac right before the problem started. My working theory is the hard shutdown and subsequent restart caused the Mac to incorrectly set the Wacom tablet as the only allowed input device for Mail and Messages.
If you’re affected by this issue, please see below for how to fix this.
1. Open System Preferences
2. In System Preferences, select the Ink preferences.
3. In the Ink preference pane, verify if the following setting is checked:
Allow me to Ink in any application
4. If the Allow me to Ink in any application setting is checked, uncheck it.
5. Close System Preferences
6. Restart your Mac (optional)
Once the Allow me to Ink in any application setting has been unchecked, the affected applications should now respond to the keyboard, trackpad and mouse.
