Players are reporting that they are getting Error Code 51 when running Rocket League. Follow the fixes below and see if they help you in launching the Rocket League without any issue.
How to Resolve the "Failed to Start Error Code 51" Problem
In generally, the problem is due to the blocking by Antivirus software, such as FSecure, Avast, AVG, Eset, Avira, Kaspersky.
VPN, Anti-Spyware, Firewall, Security software can also cause this problem. You should disable them or you can add exceptions in your firewalls for Rocket League and Steam.
Especially if you are using FSecure, you have to disable the DeepGuard to be able to play Rocket League. On the Antivirus page, select Settings. Select Viruses and Threats. Turn off the DeepGuard.
- Exit the Steam.
- Simultaneously press the Windows logo and R keys.
- Type steam://flushconfig
- Press Enter key.
- Restart the computer.
- Verify your game files. Go to the Steam library
- Right-click on the Rocket League, go to Properties.
- On the LOCAL FILES tab, press the VERIFY INTEGRITY OF GAME FILES button.
- Go to the Documents
- Open the My Games folder.
- Delete the Rocket League folder in My Games.
- Go to the list of games in the Steam library.
- Right-click the Rocket League and click the Properties.
- Click the Set Launch Options in the General tab.
- Type the following command into the space in the incoming window, then click OK.
Reinstall the Steam and Rocket League.
If the issue still exists, do let us know in the comments below.