After each step, test the issue to see if it still exists. When you move a Mac Pro (late 2013), the lights around the I/O ports does not turn on.īefore you reset the SMC, try each of these actions in the order listed above.A Mac that supports target display mode does not switch into or out of target display mode as expected, or at inopportune moments.Even though your Mac’s CPU isn’t under any especially heavy demand, it runs slowly.If present, the MagSafe power adapter LED does not show proper charging activity.External devices attached to the built-in USB-C connector on your MacBook or MacBook Pro are not recognised.The built-in USB-C port on your MacBook or MacBook Pro does not charge.The display backlight does not adjust to variations in ambient light.You can’t turn your Mac back on if it sleeps or shuts down unexpectedly.When you close or open the lid on your Mac notebook, it does not respond properly.When you push the power button on your Mac, nothing happens.On Mac notebooks with a non-removable battery, the battery indicator LEDs, if present, function erroneously.If there is a status indicator light, it behaves wrongly.

The backlight on the keyboard is malfunctioning.

Even if your computer isn’t in use and is properly ventilated, the fans on it run at a high speed.

These signs and symptoms may indicate that an SMC reset is required: How to tell if the SMC needs to be reset:

For some iMac screens, choosing an external (rather than internal) video source.

The battery status indicator is illuminated.

Management of the status indicator light (SIL).

Responding to the opening and closing of the display lid on Mac laptops.

On Intel-based Mac computers, the SMC is in charge of these and other low-level functions:

Smc fan control imac