Here’s one thing you can try: (1) Connect a DS4 controller to the PS4 using a USB cable. (2) Select option 1 in the Safe Mode menu to exit. This option will restart your console. Using this option will not affect the save data on your PS4 system. If that fails, it might be the case that a USB, power, or HDMI cable is failing. Try using different USB/HDMI/power cables, plugged into different HDMI ports and wall sockets. It is also a good idea to test your cables using a different system such as a Blu-ray player. Testing each cable and port will help identify where the issue is occurring. If all of the cables are working properly, you can try power cycling the PS4: (1) Completely turn off the PS4 by holding the power button. (2) Wait for the power light to stop flashing, then remove the power cable and leave the PS4 system for 20 minutes. (3) Reconnect the PS4 system and turn it on.
The flashing folder probably means that your Mac can't find your startup disk so it can't boot the OS. There are some things to try to fix this: First, shut down your Mac. If you can’t do it using the mouse and display, you can always just shut it down by holding the power button until the screen shuts off. Once it’s shut down, make sure everything (wires, cables, etc.) is disconnected from the Mac. Then, restart your Mac by holding the power button until the Apple logo shows up. If this doesn’t work, there are other things we can try, so don’t worry, but make sure you do this first before we continue. Tell me what happens.