Are you seeing a wall of text before Clover Boot Manager appears? If you are using macOS High Sierra and later, you are bound to see it since APFS is becoming the new file system. In macOS High Sierra, you can try and opt-out if using an installed HDD over an installed SDD as the boot drive but not so on macOS Mojave.
If you update the Clover Boot Manager, the wall of text will go away but you could have other issues since Clover often introduces bugs so you will want to update the ApfsDriverLoader.efi file alone from an updated version and verify that apfs.efi is removed.
