What should you do if your Mac won't start up properly?

Rebooting into Safe Mode is a highly effective troubleshooting step when a Mac won't start up properly. Safe Mode initiates the system with only essential processes and functionality, which helps in diagnosing and isolating issues that might be affecting the normal startup. In this mode, unnecessary background applications and extensions are disabled, allowing you to identify if a particular application or driver might be causing the startup problem.

While in Safe Mode, the Mac runs checks on the startup disk and attempts repairs if issues are detected. This is particularly useful for resolving problems that occur due to corrupted cache files or problematic startup items. If the Mac successfully starts in Safe Mode, it indicates a software-related issue, and you can work on removing or updating problematic software from there.

Resetting the NVRAM could also help resolve certain issues, but it doesn't provide the diagnostic environment that Safe Mode does. Checking for software updates typically assumes the device is already operational and isn't directly aligned with addressing startup failures. Reinstalling applications is more of a recovery step that generally wouldn't be necessary unless you can successfully boot the device into a usable state.