After a power failure during the opening or closing process, the glass sunroof can only be operated to a limited extent.
Initializing the system The system can be initialized when the vehicle is stationary and the engine is running.
During the initialization, the glass sunroof closes without jam protection.
Keep the closing path clear
Monitor closing and make sure that the closing path of the glass sunroof is clear; otherwise, injuries may result.
Press the reel up and hold it until the initialization is complete:
BMW X3 Owners Manual > Comfort Access: Malfunction
Remote control detection by the vehicle can
among others be malfunctioning under the following
circumstances:
The battery of the remote control is discharged.
Replace the battery
Interference of the radio connection from
transmission towers or other equipment
with high transmit power.
...