Quick answer
In macOS Recovery, choose Reinstall macOS to reinstall without intentionally erasing personal files.
- Back up first if possible.
- Do not choose Erase or erase a volume unless you intend to wipe that storage.
- Follow the prompts for the Mac’s Recovery options.
The startup method depends on your Mac’s processor. Apple silicon Macs use the power button and Startup Options. Intel Macs use a keyboard shortcut.
The screens and macOS version offered can vary by model and Recovery environment, so follow Apple’s current instructions for your Mac.
Before you reinstall macOS
Back up your Mac if possible, using Time Machine or another backup you know is complete. Reinstalling is designed to preserve apps and personal data, but a backup protects you if installation is interrupted or the disk has a separate problem.
2. Connect power and the internet. Keep a MacBook connected to its power adapter. Recovery may need an internet connection to download macOS; choose a reliable Wi-Fi network or use Ethernet if available.
A network sign-in page or unstable connection can interrupt the download.
3. Check compatibility and available storage. The version offered depends on your Mac model and Recovery method. Check which macOS versions your Mac supports.
If the installer reports that there is not enough storage, stop and review what can be safely moved or backed up first. Do not erase the startup disk to make room as a routine step.
Start macOS Recovery
On a Mac with Apple silicon
Apple’s Recovery startup guide shows the power-button route for Apple silicon.
Shut down the Mac. Press and hold its power button until you see the startup options screen and the gear icon labeled Options. Select Options, then Continue.
If asked, choose a user account you know and enter that Mac login password.
On an Intel-based Mac
Use Apple’s startup key guide to choose the Intel Recovery shortcut and understand which macOS version it can offer.
Turn on the Mac and immediately press and hold Command-R until you see an Apple logo or spinning globe.
If this does not open Recovery, shut down and try again with the built-in or wired keyboard. Apple documents Option-Command-R and Shift-Option-Command-R for Internet Recovery; those combinations can offer different macOS versions.
Use them only when the version offered by Command-R is not suitable or Recovery directs you to Internet Recovery.
Apple silicon Macs do not use the Intel Command-R startup method. If you are unsure which processor your Mac has, check About This Mac or use Apple’s Mac identification guidance before choosing a startup path.
Reinstall macOS without erasing the Mac
Follow Apple’s reinstallation instructions alongside the steps below.
When Recovery opens, select Reinstall macOS (the exact name can include a version), then select Continue. Follow the onscreen instructions.
If the installer asks you to unlock the disk, enter the password you use to log in to the Mac. If it offers both Macintosh HD and Macintosh HD – Data, select Macintosh HD.
Do not open Disk Utility and erase a disk or volume for this repair. Erasing deletes data.
If the only available path asks you to erase, or the startup disk does not appear, stop and read Apple’s current reinstall and troubleshooting guide before continuing.
If your files matter and you do not have a backup, contact Apple Support or a qualified service provider before taking a step that could erase the disk.
Keep the Mac connected to power and let installation finish. It may restart more than once, show a progress bar, or display a blank screen for several minutes.
Do not close a MacBook’s lid or force it to shut down while installation is in progress. When setup appears, follow its prompts.
If you were reinstalling to fix a problem, test the Mac before restoring optional software or changing many settings.
If Recovery asks for a password or will not continue
Disk unlock prompt: this is asking for a Mac user login password to unlock the startup disk. It is different from an Apple Account password.
Activation Lock: if the Mac asks for the Apple Account used with Find My, that is an ownership security check.
Use the account belonging to the owner or ask the previous owner to remove the Mac from their account. Reinstalling macOS does not bypass Activation Lock.
Do not share account credentials with a repair shop or follow bypass instructions.
Locked, missing, or unrecognized disk: do not erase it just to make the installer continue.
If Disk Utility reports an error, the disk is missing, or you cannot unlock it, stop and contact Apple Support, especially if you need files that are not backed up.
Internet Recovery error: check that the Mac is connected to the internet. Apple says globe warnings and numbered Internet Recovery errors can relate to the network. Try a different reliable network or Ethernet if available.
If the error continues, follow Apple’s troubleshooting guidance.
What reinstalling can and cannot fix
A reinstall can replace macOS system files and may help with a problem caused by the operating system.
It does not guarantee a fix for hardware faults, a full disk, a faulty peripheral, or a problem caused by a third-party app or setting.
If the same issue remains after reinstalling, stop repeating the installation and use the symptom-specific troubleshooting guide or arrange service.
For other Mac problems, see our guides to macOS compatibility and backing up with Time Machine.
Frequently asked questions
Can I reinstall macOS without losing my data?
Yes. Apple says reinstalling macOS from Recovery does not remove apps or personal data.
Back up first if possible, and do not choose Erase or erase a disk in Disk Utility.
Which Recovery keys do I use on my Mac?
Apple silicon Macs start Recovery by holding the power button until Startup Options appears, then choosing Options. Intel Macs use Command-R.
On Intel, Option-Command-R and Shift-Option-Command-R use Internet Recovery and can offer different macOS versions.
Should I choose Macintosh HD or Macintosh HD – Data?
If Recovery offers both volumes during a reinstall, Apple instructs you to choose Macintosh HD. Do not erase either volume as part of a standard reinstall.
What if Recovery asks for a password?
A disk-unlock prompt asks for a Mac login password. An Activation Lock prompt asks for the Apple Account tied to Find My.
These are different checks. If you do not own the account, ask the owner to remove the Mac; do not try to bypass the lock.
How long does reinstalling macOS take?
It varies with the Mac, the version offered, and the internet connection.
Downloading and installation can take a while and the Mac may restart several times. Keep it connected to power and wait for the process to finish.
Will reinstalling macOS fix every Mac problem?
No. It may help with some macOS system problems, but it does not guarantee a fix for hardware, storage, third-party app, or settings issues.
If the same problem remains, use targeted troubleshooting or contact Apple Support.
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