Apple MacBook Pro Retina 15 Inch Mid 2015 Quick Start Guide

To reset the SMC, shut down your MacBook Pro. Press and hold the Shift + Control + Option keys on the left side of the built-in keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds. Release all the keys and the power button, then press the power button again to turn on your Mac.
Ensure that your MacBook is connected to a power source. Perform a SMC reset as described in QA1. If it still doesn’t turn on, try resetting the NVRAM by holding Command + Option + P + R on startup. If the issue persists, consider checking the battery or visiting an Apple Store for hardware diagnostics.
Keep your software updated, avoid exposing your MacBook to extreme temperatures, and try to keep the battery charge between 20% and 80% when possible. Additionally, perform a full cycle charge (0% to 100%) once a month to calibrate the battery.
Turn off and unplug your MacBook. Use a soft, lint-free cloth slightly dampened with water or a screen cleaner. For the keyboard, use compressed air to blow out any debris. Avoid using abrasive cloths, towels, or paper towels.
Restart your router and your MacBook. Check for macOS updates and install them if available. Reset the Wi-Fi connection by turning Wi-Fi off and on again. If the issue persists, try creating a new network location under System Preferences > Network.
Close unnecessary applications and browser tabs. Keep macOS and apps updated. Consider increasing your RAM if you frequently use resource-heavy applications. Also, perform regular maintenance like clearing caches and checking for malware.
First, back up your data. Turn off your MacBook and remove the screws from the bottom case. Disconnect the battery connector and unscrew the SSD. Replace it with a compatible SSD, reconnect the battery, and reassemble the MacBook. Restore your data from the backup.
Use an HDMI or Thunderbolt 2 cable to connect your MacBook to the external display. Navigate to System Preferences > Displays to adjust the settings as needed. Ensure the display is powered on and set to the correct input.
Ensure your MacBook is on a hard, flat surface to allow proper ventilation. Check for resource-heavy applications and close them if necessary. Consider using a cooling pad and check for dust accumulation in the vents.
Go to System Preferences > Security & Privacy and select the FileVault tab. Click on the lock icon and enter your admin password to unlock the settings. Click 'Turn On FileVault' and follow the on-screen instructions to encrypt your disk.