It is likely that either the mouse buttons are not recognized as individual buttons, or there is no default action assigned to these buttons. The solution depends on what program you are trying to use these buttons in.
Operating System: Only mice 1 and 2 (left click and right click) will have default actions assigned. This means that using your extra buttons will have no effect by default.
Games and programs: There are a few different kernel-level drivers that handle USB device input for games and programs but most will only recognize up to mouse 5 (left click, right-click, scroll wheel click, side button 1, side button 2).
The most common method to gain the functionality of buttons that are not assigned or recognized by default is to use keyboard macros. You can assign macros by using SteelSeries Engine 3 with supported devices. Our older devices use varying software packages that can be found on our downloads page.
By using SteelSeries Engine, you can also create different profiles for different games and programs, so that you do not need to constantly re-assign macros.
The most common macros we recommend for mice are:
Key emulation macros - assigning a single keyboard key to a mouse button so you can press and hold it
Key combination macros - these macros are input one time per click and cannot be held. They're comprised of multiple keys being pressed at the same time (ie. ctrl + C)
String macros - these are macros that instantly type a set string for you with the press of one button (ie. Hello, welcome to SteelSeries!)
If you are having issues outside of what is stated above, try re-installing your device drivers by following the instructions here.