Microsoft Natural Ergonomic Keyboard function keys unreliable

I have a Microsoft Natural Ergonomic Keyboard connected to my 2011 MacBook Pro.

The keyboard's normal keys (letters, etc.) always work fine; however, there is a problem with the various function keys.

Basically, they don't work until I go to System Preferences -> Microsoft Keyboard. Once I go to that prefpane, everything starts working again.

It seems to somewhat randomly stop working, requiring me to go to System Preferences again to make it work.

How can I fix this? It seems like a daemon/driver that's supposed to make the keys work is crashing, but I searched Console.app for microsoft with no luck.

The reason for this is that Microsoft Keyboard Helper is somehow not being added to the Login Items by the keyboard's driver installer. However, the helper is contained inside the Microsoft Keyboard Preference Pane, so it is being run when you open it, and thus restores the full functionality of the keyboard.

The simple solution is this:

1. Open System Preferences;
2. Go to Users & Groups > {your user} > Login Items;
3. Click + icon under the Login Items list;
4. When Finder window opens, press ⇧ + ⌘ + G;
5. When a form appears, paste this into it: /Library/PreferencePanes/Microsoft Keyboard.prefPane/Contents/Resources/;
6. Select the file MicrosoftKeyboardHelper, and press Add;

That's it. The keyboard should now retain its function keys' functionality after the restart.

I also have the Microsoft Natural Ergonomic Keyboard. In my case the simple solution was to press the F Lock key at the far right of the function row (left of the Print Screen button). I didn't realize the button even existed until now.