Recently we notice some reports that Mac users might encounter white screen issue after they upgrade macOS to the latest Sierra, and the computer just get stuck on the screen after a start up chime. In many other cases when there is an error or issue with macOS, Mac will stop functioning properly and display a blank white/gray screen.
There can be many reasons lying behind the phenomenon. If your Mac fails to boot up normally or power up as expected, how to deal with it? We hereby summary a few troubleshooting techniques that you can try to fix your Mac white screen issue.
Safe Mode is a way to start up your Mac so that it performs certain checks like verifying your startup disk, repairing directory issues, deleting system cache files, etc.
To successfully enter Safe Mode, you need to press and hold the Shift key after the star up sound/chime before the Apple logo appears. If your Mac works fine in safe mode, reboot your Mac again without pressing any keys during startup to exit Safe mode. If the issue persists in normal mode again, you might have incompatible login items. If your Mac boot up normally, then the white screen issue is possibly caused by a cache/directory issue with your startup disk that has been fixed by Safe Mode.
If the white screen issue is related to the boot disk that Safe Mode fails to fix, try the Disk Utility to perform a comprehensive check.
PRAM (parameter random-access memory) stores some of your settings including speaker volume, screen resolution, startup disk selection and recent kernel panic information. In some cases simply resetting NVRAM is sufficient to remedy the white screen issue. To do so, reboot your Mac, and hold down the Command+Option+P+R keys as you hear the boot chime. When you hear the second boot chime, you can let go the keys as the NVRAM has been reset, and then you can boot your Mac normally.
If all the available ways you have tried don’t help, reinstalling your macOS is the last resort to fix white screen issue. Make sure to back up your Mac before doing this.
Has your issue been resolved yet? Many other ways are not included in this post yet. If all solutions you can find fail to work, you’d better contact Apple Support for help.