When you open Malwarebytes for Mac, you may encounter the error message Background service is offline, as seen in the picture here.
Use the solutions suggested below to resolve the error message and use Malwarebytes for Mac.
Solution 1: Update Malwarebytes for Mac
Malwarebytes for Mac v3.0.3 and earlier use the System.keychain file, which causes the error message you are experiencing. The latest version of Malwarebytes for Mac does not rely on the System.keychain file. To update to the latest version, see Download and install Malwarebytes on Mac device.
Solution 2: Restart the computer
If you have Malwarebytes for Mac v3.1 or later installed, restart your computer.
Solution 3: Reinstall Malwarebytes for Mac
If restarting fails, your installation of Malwarebytes for Mac may be corrupted. See Download and install Malwarebytes on a Mac device to repair and restore corrupted files.