- Close the Bitdefender application and rerun it on your computer to check if the Bitdefender Error Code 501 appears again.
- If the error appears, check if you have a standard Internet connection for your device.
- Click the Start menu from the taskbar and navigate to the Control Panel.
- Select the Programs and Features tab and choose all the available security applications installed on your device except Bitdefender.
- After selecting the application, click the Remove or Uninstall option to delete the additional security applications.
- Make sure to disable the in-built security application (Windows Defender) on your computer.
- Also, update your computer to the latest OS version.
- Check if your Bitdefender license has expired.
- If your application's validity was ended, you cannot use the Bitdefender software further.
- Make sure that the Bitdefender is compatible with your computer.
- Now, rerun the Bitdefender Antivirus software and check if the error appears again.