Did you do all the following steps?
1. When Mach3 is installed , there will be a folder created named “PlugIns” in the Mach3 folder. This folder is the location to put and Plugin files that you want Mach3 to know about. Place “XHC-ShuttlePro.dll” in the Mach3\PlugIns folder. Check and make sure it is there.
2. Now that the XHC-ShuttlePro.dll file is in \Mach3\PlugIns, the next step is to connect the ShuttlePro. If you are certain that your ShuttlePro is working and your hardware is working then you can simply plug in the ShuttlePro to one of the USB ports.
3. Once the ShuttlePro is connected, start Mach3 and go to the “Config” menu
choice and select “ConfigPlugins”. You should see the ShuttlePro choice with a green checkmark in front of it. If it is not checked, you can check it. The
checkmark means that Mach3 found the ShuttlePro on startup. Click the “CONFIG” in yellow and set the buttons as you wish.
4. Once you have the proper button selected in the Mach3 ShuttlePro Plugin
CONFIG menu, your Shuttle device should be working properly.