My mac will not turn on. When i turn it off i hear a swish sound after 8 seconds. I try turning it back on it doesn't do anything.

Joykauf wrote:

When i turn my mac off i hear a swish sound after 8 seconds. I try turning it back on it doesn't do anything and I have a black screen.

If this is an Intel Mac..(?) you can try both

resetting the SMC https://support.apple.com/en-us/HT201295

resetting NVRAM/PRAM http://support.apple.com/kb/ht1379

(get at least two-three rounds of the chimes when holding the NRAM Reset)

That used to be the sound that certain 2018+ Apple laptops with the T2 security chip made when performing an SMC Reset while the laptop was powered on. I have not heard that sound in a long while so I think a more recent macOS update has changed that behavior with the sound so I suggest making sure you have the latest macOS patches installed for your current OS.

I am also encountering issues powering on Apple USB-C laptops after an SMC Reset even with a fully updated macOS. Sometimes you need to unplug the charger for a few seconds and plug the charger back in. Then try powering on the laptop again. Sometimes you may have to wait a few minutes and the laptop will automatically power on by itself. If that does not work, try connecting the charger to another USB-C port especially on the other side of the laptop if you have the four port model.

I have not been able to determine any hardware issues with the laptops exhibiting this behavior. I believe this is just Apple doing a terrible job with hardware design and implementation and poor system firmware. This is just one of many disturbing behaviors I've encountered with these Apple USB-C laptops and it makes troubleshooting these laptops an extremely difficult process.