I have a 2019 MacBook Air, and I had had this problem for years now (possibly from the start). The MacBook doesn't start up when it is on battery power unless I press the power button repeatedly at least 3 or 4 times.
Maybe this is normal, im not sure. if it is, is there a way to simply start up the computer simply by pressing the power button once?
Try an SMC Reset. Make sure to read the instructions carefully since the process has changed for 2018+ models using the T2 security chip.
Reset the SMC of your Mac - Apple Support
On these 2019 laptops you should be able to power on the laptop by pressing any key, opening the lid, or connecting the charger. Does the laptop power on or wake up using these alternate methods?
Are you trying to wake the laptop or are you trying to power on the laptop from a full power off state?
I'm assuming you are not seeing the battery icon on the screen to indicate that the charger needs to be connected?
Make sure to disconnect all external devices in case one of them is causing a problem.
Try running the Apple Diagnostics to see if any hardware issues are detected. If it passes, then you may still want to take the laptop to an Apple Store or Apple Authorized Service Provider to be examined.
Try an SMC Reset. Make sure to read the instructions carefully since the process has changed for 2018+ models using the T2 security chip.
Reset the SMC of your Mac - Apple Support
On these 2019 laptops you should be able to power on the laptop by pressing any key, opening the lid, or connecting the charger. Does the laptop power on or wake up using these alternate methods?
Are you trying to wake the laptop or are you trying to power on the laptop from a full power off state?
I'm assuming you are not seeing the battery icon on the screen to indicate that the charger needs to be connected?
Make sure to disconnect all external devices in case one of them is causing a problem.
Try running the Apple Diagnostics to see if any hardware issues are detected. If it passes, then you may still want to take the laptop to an Apple Store or Apple Authorized Service Provider to be examined.
Macbook in need of power button to be pressed multiple times repeatedly to start up
