What restoring to factory settings does
Restoring your iMac to factory settings erases everything on the computer — all your files, programs, and settings — and reinstalls the original operating system that came with the machine. This is different from restarting or updating. You end up with a blank iMac that looks and works exactly as it did the day it left the factory.
People do this when the computer has become slow or unstable, before selling or giving away the machine, or when they want a completely clean start. The process takes between one and three hours depending on your internet speed and which iMac model you have.
Once you start, you cannot stop partway through without losing data. Back up everything you want to keep before you begin.
Key Takeaways
- Back up all your files to an external drive or cloud storage before you start, because the restore process deletes everything on your iMac.
- The method you use depends on which macOS version your iMac currently runs — newer Macs use one method, older ones use another.
- You will need a stable internet connection for the entire process, which can take one to three hours.
- After the restore finishes, your iMac will restart and ask you to set it up as if it were brand new, just like the first time you turned it on.
Back up your files before you do anything
The restore process erases your entire iMac. If you have files, photos, documents, or anything else you want to keep, you must copy them somewhere else first. You have two main options.
External drive backup: Plug in an external hard drive or USB drive with enough space for all your files. Open Finder, click on your iMac's name in the sidebar, select all your files (Command + A), and drag them to the external drive. This takes longer but gives you a complete copy you can access anytime.
Cloud backup: Upload your important files to iCloud, Google Drive, Dropbox, or another cloud service. You can do this one folder at a time or set up automatic backup. This is slower for large amounts of data but means your files are safe even if the external drive fails.
Do not skip this step. Once you start the restore, there is no way to recover files you did not back up.
How to restore an iMac running macOS Big Sur or newer
If your iMac is running macOS 11 (Big Sur) or later, use this method. You can check which version you have by clicking the Apple menu in the top left corner, selecting "About This Mac," and looking at the "System Software" line.
Step 1: Shut down your iMac completely. Wait 30 seconds, then turn it back on. As soon as you see the Apple logo, hold down Command + Option + R together. Keep holding until you see a spinning globe or the macOS Recovery window. This loads the recovery system from Apple's servers.
Step 2: When the recovery window appears, you will see a list of tools. Click "Erase Mac" (or "Reinstall macOS" if that is the only option you see). A new window will open asking you to select the disk to erase. Click on "Macintosh HD" or whatever your main drive is called, then click "Erase."
Step 3: The system will ask you to confirm. Type your iMac's password if prompted. The erase process starts and shows a progress bar. This takes 10 to 20 minutes. Do not turn off the iMac or unplug it during this time.
Step 4: After the erase finishes, the iMac restarts automatically. You will see the macOS installation begin. This downloads the original operating system from Apple's servers and installs it. This is the longest part and can take one to two hours depending on your internet speed. Your iMac will restart several times during this process — this is normal.
Step 5: When installation finishes, your iMac restarts one final time and shows the setup screen, just like a brand new computer. You can now set it up with your Apple ID, create a new user account, or leave it blank if you are giving it to someone else.
How to restore an iMac running macOS Mojave or older
If your iMac is running macOS 10.14 (Mojave) or an earlier version, the process is slightly different. You will use Internet Recovery instead of regular Recovery.
Step 1: Shut down your iMac completely. Turn it back on and immediately hold Command + Option + R. You will see a spinning globe appear. Keep holding the keys until the macOS Recovery window opens. This can take a few minutes because it is downloading the recovery system from the internet.
Step 2: In the recovery window, click "Disk Utility." A new window opens showing your hard drive. Click on "Macintosh HD" or your main drive name on the left side, then click the "Erase" button at the top.
Step 3: A dialog box asks for a name and format. Leave the name as "Macintosh HD" and make sure the format is set to "Mac OS Extended (Journaled)." Click "Erase" and confirm. The erase takes 10 to 20 minutes.
Step 4: When the erase finishes, close Disk Utility and you will be back at the recovery window. Click "Reinstall macOS" or "Reinstall OS X" depending on your version. Follow the prompts to reinstall the original operating system. This downloads from Apple's servers and takes one to two hours.
Step 5: Your iMac restarts multiple times during installation. When it finishes, you will see the setup screen. Your iMac is now restored to factory settings.
What to do if the restore gets stuck or fails
If your iMac gets stuck on a progress screen for more than 30 minutes, or if you see an error message, the most common fix is to restart and try again. Hold the power button for 10 seconds until the iMac shuts down completely, wait one minute, then turn it back on and repeat the restore process from the beginning.
If you keep getting the same error, your internet connection may be dropping. Move your iMac closer to your WiFi router or plug in an ethernet cable if you have one. A weak or unstable connection is the most common reason restores fail partway through.
If the restore fails multiple times even with a strong connection, your iMac's hard drive may have a problem. In that case, you will need to take it to an Apple Store or a repair shop that works on Macs. They can run diagnostics and replace the drive if needed.
After the restore is complete
When your iMac finishes restoring and restarts, it will ask you to set it up as if it were brand new. You will choose a language, connect to WiFi, and either sign in with an Apple ID or skip that step. You can restore your backed-up files at this point by plugging in your external drive or signing into your cloud storage account.
If you are giving the iMac to someone else, you can stop at the setup screen and let them complete the setup with their own Apple ID. If you are keeping it, sign in with your Apple ID and then restore your files from backup.
Your iMac will run noticeably faster after a factory restore because it no longer has years of accumulated files, caches, and old program data slowing it down. This speed improvement usually lasts for several months before the iMac gradually slows down again as you add new files and programs.
Frequently Asked Questions
Will I lose my Apple ID or iCloud data if I restore to factory settings?
Your Apple ID itself is not stored on your iMac — it is stored on Apple's servers. After the restore, you can sign back in with the same Apple ID and your iCloud data (photos, documents, contacts) will sync back to your iMac. Files you stored only on your iMac will be gone unless you backed them up separately.
Can I restore my iMac without an internet connection?
No. The restore process downloads the operating system from Apple's servers, so you need a working internet connection for the entire process. If your WiFi is unreliable, use an ethernet cable plugged directly into your iMac if it has an ethernet port, or move closer to your router.
How do I know if my iMac is using an Intel processor or Apple Silicon?
Click the Apple menu, select "About This Mac," and look at the "Processor" line. If it says "Intel" or lists a specific Intel model, you have an Intel iMac. If it says "Apple M1," "M2," or similar, you have an Apple Silicon iMac. Both use the same restore method, but Apple Silicon iMacs are newer and restore faster.
What if I forgot my iMac password and cannot complete the restore?
If you are locked out of your iMac, you can still restore it to factory settings using the recovery method described above. The recovery system does not require your password to erase the drive. However, if you set up FileVault encryption, you may need your password to proceed. If you have completely forgotten it, you will need to contact Apple Support or visit an Apple Store.
Can I restore just one part of my iMac instead of everything?
No. A factory restore erases and reinstalls everything. If you only want to remove certain programs or files, restart your iMac normally and delete them individually. If your iMac is running slowly, try restarting it first — that often fixes slowness without erasing anything.