Restart and hold the Option key to access the Startup Manager and select your startup disk. 2. Boot into Recovery Mode using Command R, then check or change the startup disk in the Startup Disk utility. 3. Use Disk Utility’s First Aid to repair the internal drive if it appears but won’t mount. 4. Reset NVRAM (Option Command P R) and SMC on Intel Macs; Apple Silicon Macs only require a restart. 5. Reinstall macOS from Recovery Mode to fix corrupted system files without erasing data. 6. Run Apple Diagnostics by holding D during startup to check for hardware issues like SSD or logic board failure. 7. Restore from a Time Machine backup if all else fails, or attempt data recovery if no backup exists. A flashing folder with a question mark indicates the Mac cannot find a valid startup disk, but most cases can be resolved through these steps, with hardware failure being a less common cause.

A flashing folder with a question mark on your Mac means the system can’t find a valid startup disk to boot from. This can be scary, but it’s usually fixable. Here’s what to do, step by step.

1. Restart and Hold the Option Key

Sometimes the Mac just needs a nudge to find the right startup disk.

• Shut down your Mac.
• Press the power button, then immediately hold down the Option (?) key.
• Keep holding it until you see the Startup Manager screen with available drives.
• If your startup disk appears (usually named “Macintosh HD”), click it or use the arrow keys to select it and press Enter.

? This often resolves temporary boot glitches.

2. Check the Startup Disk in Recovery Mode

If the above doesn’t work, boot into Recovery Mode to diagnose the drive.

• Shut down your Mac.
• Turn it on and immediately hold Command (?) R until you see the Apple logo or a spinning globe.
• When the macOS Utilities window appears, choose Startup Disk.
• If your drive appears here, select it and click Restart.
• If the drive doesn’t appear, it could be disconnected, failed, or unmounted.

? If the drive is visible but grayed out, it might need repair.

3. Run First Aid Using Disk Utility

Still in Recovery Mode:

• Open Disk Utility from the macOS Utilities menu.
• In the left sidebar, look for your internal drive (likely named "Macintosh HD" or your SSD model).
• Select it and click First Aid (the wrench icon).
• Wait while Disk Utility checks and attempts to repair the disk.

?? If First Aid fails or says the disk can’t be repaired, the drive may be failing or corrupted.

4. Reset NVRAM/PRAM (Older Macs) or SMC

These steps help if firmware settings are interfering.

For Intel Macs:

• Reset NVRAM: Shut down, then turn on and immediately press Option Command P R. Hold for about 20 seconds.
• Reset SMC: Shut down, then press Shift Control Option Power (on built-in keyboard) for 10 seconds, then release and power on.

For Apple Silicon (M1/M2 Macs):

• SMC and NVRAM resets aren’t needed. Just shut down and restart—that handles most low-level resets.

5. Reinstall macOS (Without Erasing Data)

If the drive is intact but the system can’t boot:

• In Recovery Mode, choose Reinstall macOS.
• Follow the prompts. It will download and install the OS without erasing your files (as long as the drive is accessible).

? This often fixes corrupted system files while preserving your data.

6. Check for Hardware Issues

If none of the above works:

• The internal SSD or logic board connection may be faulty.
• For Macs with removable storage (older models), check if the drive is properly seated.
• Use Apple Diagnostics: Restart and hold D during boot to run a hardware test.

? If diagnostics detect a hardware failure, contact Apple Support or visit an Apple Store.

7. Restore from Backup (Last Resort)

If the drive is wiped or failing:

• Boot into Recovery Mode.
• Use Restore From Time Machine Backup to get your system back.
• Make sure you have a recent backup. If not, connect an external drive and attempt data recovery using Disk Utility or third-party tools.

Bottom line: A flashing folder usually means the Mac can’t locate the startup disk. Most issues can be resolved with Recovery Mode, First Aid, or reinstalling macOS. Hardware failure is less common but possible—especially on older Macs.

Basically, start simple: restart with Option, then move to Recovery tools. Most cases aren’t permanent.

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