If your PS4 system starts up in safe mode with directions to connect a USB storage device it means you need to reinstall the system software. This is only recommended for systems that cannot start normally because it will delete all data from the hard drive. You will need… a computer that’s connected to the Internet and a USB flash drive or a “thumb” drive that’s in FAT32 or exFAT format that has at least 1.1 GB of free space. Go to www.playstation.com and open the [Help] menu at the top. Select [System Software]… followed by [PS4]. Scroll down past the current system software release to find the
“PS4 Complete System Software File” and download the file. Connect your USB storage device to the computer. Create a folder named “PS4” on the device. Make an “UPDATE” folder inside the PS4 folder. Copy the software file into the UPDATE folder. Make sure the file is named “PS4UPDATE.PUP” because your computer might add extra characters you’ll need to delete. The names of the file and the folders must be in all capital letters. Connect the USB device to your PS4 system… select [OK]… and follow the directions to reinstall the system software. If the file cannot be found you should double check that the file and folders are named correctly in all capital letters and then try again. If the PS4 does not support the USB device’s file system… you’ll need to reformat the device as ExFAT or FAT32 before following these directions again.