Perform the following steps to disable a Steam Controller:
- In Steam, click on the Big Picture Mode button in the upper-right corner
This will open Steam in Big Picture Mode in full screen - Click on the Library button
- Select Rocket League
- Click on the Manage Game button in the left-hand column
- Click on the Controller Options button
- Click the Steam Input Per-Game dropdown box
- Select Forced Off
- Launch Rocket League to confirm that your controller is recognized
Note: If your input is still not being recognized, you may need to relaunch Rocket League.