What causes overheating when idle?

Overheating when a device is idle can be caused by several factors, including dust buildup that restricts airflow, malfunctioning cooling fans, or software processes that continue to run in the background, consuming CPU resources. Additionally, inadequate thermal paste on the CPU or GPU can lead to poor heat dissipation. Ambient temperature and poor ventilation can also contribute to increased temperatures, even when the device is not actively in use.