Mac stuck on a gray screen at startup

Symptoms

• Screen turns gray during startup and doesn't progress further
• No spinning wheel or progress bar appears
• Problem happens consistently across multiple restart attempts
• Issue may be linked to a recently connected external device

Likely causes

• CommonA startup disk with file system errorsDisk Utility's First Aid is specifically designed to catch and fix this.
• CommonA connected external device interfering with startupCertain USB or Thunderbolt devices can occasionally prevent normal boot.
• PossibleA failed or interrupted macOS updateThis can leave the system in a state where it can't fully load.
• PossibleNVRAM/PRAM settings needing a reset (Intel Macs)Corrupted startup-related settings can cause this kind of stall.
• PossibleA failing startup driveIn more serious cases, the drive itself may be having read errors.

What to do

1. Disconnect all non-essential external devices (drives, hubs, printers) and try restarting.
2. Force a restart by holding the power button for about 10 seconds if the gray screen persists.
3. On Intel Macs, reset NVRAM/PRAM by holding Option+Command+P+R during startup until you hear the startup sound twice.
4. Boot into macOS Recovery and run Disk Utility's First Aid on the startup disk to check for and repair errors.
5. If First Aid finds significant problems, back up any accessible data before proceeding further.
6. Try reinstalling macOS through Recovery if First Aid alone doesn't resolve the startup issue.
7. If you recently added RAM or another internal component yourself, double check it's properly seated.
8. If the gray screen persists across all these steps, especially with no external devices connected, professional diagnosis is the next step.

Tools and parts

• None required

When to call a pro

If Disk Utility can't repair the drive or the gray screen persists after a macOS reinstall attempt, an Apple-authorized shop can assess for hardware failure and attempt data recovery.

Safety