How to fix Error 577 Malwarebytes
The “Security and Maintenance” Control Panel applet may warn you that Windows Defender is disabled and no anti-virus is protecting your system. If you open Windows Defender interface, it offers to Turn On protection, but the button doesn’t work.
In the Services MMC, when you try to start Windows Defender Antivirus Service or Windows Defender Antivirus Network Inspection Service, you may get Error 577, as seen below:
Fix: Windows Defender Error 577 – Service fails to start
This problem can happen if you’ve been using a 3rd party anti-virus solution and later uninstalled it or its trial period has ended. Installation of a third-party anti-virus program automatically disables Windows Defender anti-virus. If a trial version of your anti-virus software (i.e. Avast, McAfee, Norton, etc) came preinstalled on your computer (or you installed one), it most likely turned Windows Defender off to avoid conflicts.
Until the third-party anti-virus software has been completely uninstalled, Windows Defender will remain disabled. Sometimes, you’ll need to download and run the anti-virus software vendor’s uninstaller/cleanup tool to remove traces of the software completely. Once done, Windows Defender and the related services should resume automatically.
Step 1: Uninstall third-party anti-virus software
Open Apps & Features or Programs and Features and uninstall the third-party software. If the uninstall process fails, or the uninstall doesn’t fix the problem even after restarting the system, use the specialized cleanup tool from the respective anti-virus software vendor.