Troubleshooting guide
How to fix the problem
Check if the disk is visible in Disk Utility; if so, First Aid, Startup Disk and, if necessary, reinstalling macOS without erasing the disk according to Apple's instructions. Backup priority.
Possible solutions
Choose the method that matches your situation. Start with the simplest suitable option and check the result. If the problem is fixed, you do not need to continue with the other methods.
Choosing a startup disk
If Recovery detects a healthy disk, check the Startup Disk and select the correct system.
Steps to follow
- According to the type of Mac, open Recovery: Apple silicon - holding power until Options; Intel - Command+R on boot.
- In Disk Utility, select View > Show All Devices and see if your drive is detected. Unlock legally if needed.
- If the disk is present, in the Startup Disk menu of the Recovery Apple, when available, select the appropriate boot system and reboot.
- If the drive is missing or unstable, do not format. In the case of a circle with a dash, also check the macOS supported by the model.
Disk Utility First Aid
Once you have a copy, check the drive from Recovery according to Apple's procedure.
Steps to follow
- Save a copy before editing; an unstable or undetectable drive requires data evaluation first.
- Open the appropriate Recovery and Disk Utility > View > Show All Devices for your model.
- In Apple's order, start with volumes, then containers, and finally the device itself, choosing First Aid > Run for each. Enter the key only if you need a legitimate unlock.
- Write down the result and reload. If it doesn't fix or the drive disappears, don't press Erase to save the files.
Reinstalling compatible macOS
If the disk is stable and the system is damaged, follow the official procedure to install without erasing, having a copy first.
Steps to follow
- Before reinstalling, have a verified copy of the files and make sure the drive is detected stably.
- Open the appropriate macOS Recovery for your model and view the status in Disk Utility if necessary; do not erase the disc.
- If the official instructions call for installing a compatible macOS on an existing system, choose Reinstall macOS and an existing system volume.
- Follow the wizard with power and connection. If it asks to delete, the options don't match, or there is no copy, stop and ask for help.
If the problem persists
If the disk is visible and the check is successful, check the Startup Disk option. Consider installing macOS on an existing system only with a copy and without erasing the drive; start with diagnostics when the disk disappears.
Request a repair