OS X: Gray progress bar appears under Apple logo during startup
If you see a gray progress bar while your computer is starting up, OS X may be attempting to diagnose and resolve an issue with your startup drive.
When you see a progress bar at startup
If you didn't shut down your computer properly, or if OS X detects issues with your startup drive, you may see a progress bar the next time you start up your computer.
After OS X finishes repairing the startup disk, you should see the login screen, or your desktop like you normally would. If your computer isn't able to finish starting up, try starting from OS X Recovery and use Disk Utility to try to repair any disk issues. See the "Try Disk Utility" section of this article for instructions.
If Disk Utility finds issues it can't repair and you have a backup, you may need to erase the hard drive. After erasing and reinstalling OS X, restore your Time Machine backup or important files you backed up.
Other reasons you might see a progress bar
You may see a progress bar when restarting or waking your computer for other reasons:
- You may see a progress bar when waking your computer from sleep, this is a feature of Safe Sleep.
- If you've installed system updates, you may see a progress bar the first time your computer restarts after installation.
- If you've started up the computer in Safe Mode, OS X verifies your startup disk as part of the Safe Mode startup process. A progress bar appears until the disk check is complete.
Important: If you are unable to start up your computer, or the progress bar appears every time you restart (not wake) your Mac, you should back up your important data. This may indicate a drive issue that could potentially lead to data loss. Use Time Machine or another app to back up your system to a different disk, or manually copy your important files to an external drive using the Finder.