What does the red "BRAKE" light mean on a BMW X5?

the emergency brake was engaged

It could be as simple as one of the brake light bulbs are out. Start there.

Did she took longer then usual to make it home?
If so, it could be the signal that the handbrake was still on.

“the emergency brake was engaged” : That is the Park Brake light. This light was next to that one, and it only said “BRAKE”

@metadog ~ sorry, I meant hand brake, like @rebbel said

Check the brake/turn lights and if they’re all working fine- take it in. Could be a mileage-related checkup. Some cars alert you when so many miles have gone by without having the switch reset by a mechanic- like when they check your brakes.

I just fired it up myself. The “BRAKE” light is on and when you turn the car off the message “check break linings” shows up on the screen.

BMW uses brake pad wear sensors to monitor the condition of your brake pads. Although your BMW has eight brake pads, on most models, only two pads are monitored for wear – the driver’s side front inboard pad and the passenger’s side rear inboard pad. Thus, you should only order one front and one rear sensor. When a monitored pad has worn below 2mm, the rotor chews through a plastic bump on the sensor and slices a wire. This causes an open circuit, triggering a warning on your dash, either an idiot light or “CHECK BRAKE LININGS” message. Once a warning has appeared, the sensor has been destroyed and must be replaced.

souce

PS google is your friend :)
Welcome to Fluther.

For me, it has usually meant that my brake fluid is low, though there were a few times where I didn’t fully release the parking brake.

However, with the fancier new cars, especially the high-end ones lie a BMW, there are often sensors as @Axemusica points out, and since you actually got a plain-text message regarding the linings, I believe that he has the details right in your case.

@Axemusica GA to you, and have a happy weekend :)

Thanks @jerv you too. When I saw the “Check brake linings” I knew it had to do something with a sensor or brake pads, but I had to find some evidence, lol.

Personally, I visually check my brake pads and shoes periodically anyways, so that sort of sensor is pretty useless for me since I’ll know before it does.

@jerv ditto. :) 

already replaced my 2006 BMW X5 sensors and break pads but I still get the check brake lining lights

@tonyfe78 Did they put the right pads in the right places?