Ignition off.
Before you book an expensive service appointment, try these "soft reset" methods.
If your screen is frozen, black, or stuck on the logo, a soft reset often fixes the issue without deleting your settings.
If you have tried the resets above and are still experiencing issues, you may have a hardware problem rather than a software one.
A-Class, new C-Class (W206), GLC, and newer models with the touchscreen MBUX system.