If you are having issues reinstalling OS X using the built-in recovery system, there are a few things you can try to get it working again. The recovery system is designed to allow you to reinstall OS X without any other disks or drives, but sometimes it can fail or encounter errors. Don’t panic – in most cases you can still reinstall OS X using an external drive.
Quick Diagnosis
First, let’s go through some quick checks to diagnose why the recovery system is not working properly on your Mac:
- Is your Mac able to boot to the recovery partition? Hold down Command-R while turning on your Mac. If you see the OS X Utilities screen, recovery is working at least partially.
- Is your disk formatted as Mac OS Extended (Journaled)? The recovery partition requires this format. You can check in Disk Utility.
- Is your diskencrypted with FileVault? FileVault can interfere with the recovery partition.
- Is your disk healthy? Go to Disk Utility and verify/repair the disk if errors are found.
- Is your Mac compatible with the version of OS X you are trying to install? Check compatibility before reinstalling.
If you are still unable to boot to the recovery partition or reinstall OS X, don’t worry – you can use an external OS X installer instead. Just follow the steps below.
How to Reinstall OSX Using an External Drive
To reinstall OS X using an external drive, you will need the following:
- An external drive, such as a USB stick or hard drive, with at least 12GB of available storage
- A connection to the internet
- Power adapter for your Mac
Here are the steps to reinstall OS X:
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Connect the external drive to your Mac and make sure it is formatted for Mac (as Mac OS Extended).
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On another Mac, go to the App Store and download the version of OS X you need for your Mac. Quit the installer if it launches automatically after downloading.
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Open the Terminal app and enter this command (replace “InstallerName” with the name of your installer):
sudo /Applications/Install\ OS\ X\ InstallerName.app/Contents/Resources/createinstallmedia --volume /Volumes/ExternalDriveName --applicationpath /Applications/Install\ OS\ X\ InstallerName.app -
This will create a bootable installer on your external drive. It will erase the disk so make sure you have backups.
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With the drive still attached, restart your Mac and hold down the Option key. Select the external drive to boot from it.
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Open Disk Utility and erase your internal disk (the one you want to reinstall OS X on). Choose Mac OS Extended format.
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Quit Disk Utility and run the OS X installer from the external drive. Follow the prompts to install OS X on your internal disk.
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Once installation is finished, you can reboot directly to your internal disk and start using your Mac again!
Using this process with an external USB drive, you can reinstall the latest version of OS X even if the built-in recovery system is not working properly. The external installer bypasses recovery to give you a fresh copy of OS X.
Common Recovery Partition Issues
There are a few common issues that can prevent the recovery partition from working properly. Here are some things to look out for:
Corrupt Partition
The recovery partition can become corrupted from disk errors or FileVault encryption. You may see errors about “an invalid node structure” when trying to use recovery. Unencrypting your disk with FileVault or reformatting the drive can resolve this issue.
Incompatible OS Version
If OS X was upgraded since the recovery partition was created, it may no longer match what recovery is trying to install. Updating to a newer OS X version than what recovery supports will require an external installer.
Secure Boot Errors
On newer Macs, Secure Boot may interfere with the recovery partition. Disabling Secure Boot can allow recovery to work again. You can disable it in Startup Security Utility.
Missing Partition
The recovery partition could have been erased or removed somehow. You may see a message about a missing partition. An external installer will be required.
Disk Utility Errors
Sometimes Disk Utility itself has issues during recovery, failing to erase or format the disk properly. You may need to try a different disk utility like Drive Genius from an external drive.
Recreating the Recovery Partition
If your internal recovery partition is completely non-functional, you can recreate it without an OS reinstall. Here’s how:
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Boot to an external OS X installer drive.
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Open Terminal and enter:
diskutil listThis will show all your disks. Make note of the disk identifier for your internal disk (not the external installer disk).
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Enter the following in Terminal, replacing “disk #” with your actual disk number:
diskutil unmountDisk /dev/disk# -
Next type:
recoveryDiskCreator -writerRecovery /dev/disk#This will recreate the recovery partition on your internal disk.
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Restart your Mac and test that recovery boots correctly now.
The recoveryDiskCreator command cannot copy your original OS X system files, but it will make the partition bootable again so you can reinstall OS X normally.
Tips for Avoiding Recovery Issues
To help avoid recovery partition problems in the future, here are some best practices:
- Do not manually remove or alter recovery partitions
- Use Disk Utility’s “Repair Disk” option regularly to fix disk errors
- Maintain up-to-date Time Machine backups you can restore from
- Disable FileVault encryption before doing major OS updates
- Use Apple’s official uninstall process before downgrading OS X versions
Following these tips will help maintain a healthy recovery partition and regular backups, giving you more options to reinstall OS X securely.
Seeking Professional Help
If you have tried all of the self-service steps above and are still unable to get the recovery partition or OS X reinstall working, it’s best to seek professional assistance. An Apple technician, authorized service provider, or data recovery specialist can diagnose what is preventing recovery from working on your specific Mac.
Professionals have access to internal Apple resources and diagnostics to fully determine why built-in recovery is failing. They can check for hardware issues like disk drive failure, or boot disk corruption that may require advanced forensics or data recovery techniques to resolve. While these services can have higher costs, they have the best chance of getting your Mac and OS X install functional again.
Frequently Asked Questions
Why does my Mac say the recovery partition is missing?
If you see errors about a missing recovery partition, it likely has been erased or damaged. Check in Disk Utility to see if the recovery partition is still shown. You may need to recreate the partition, or reinstall OS X with an external installer disk.
Can I recover data from my Mac before reinstalling OS X?
Yes, connect your disk to another Mac and copy your data to an external drive. Or use data recovery software to extract data before wiping your disk. Just avoid restoring system settings that may be corrupted.
How can I troubleshoot kernel panics during recovery?
Kernel panics during recovery are often hardware related – bad RAM, disk drives, loose internal cables. Try resetting NVRAM or testing hardware in Apple Diagnostics mode. Safe Mode may also help.
What if my Mac is too old for the latest OS X version?
You can download older OS X installers from Apple if your Mac is no longer compatible with the latest version. Look for installers that originally shipped with your model.
Can I still get help from Apple if my Mac warranty has expired?
Yes, Apple and its authorized service providers will still diagnose and repair issues on your Mac for a fee after warranty expiration. Extended AppleCare coverage also available.
Conclusion
Reinstalling OS X using recovery boot can be a convenient process, but is susceptible to problems like partition corruption, incompatible OS versions, and disk errors. In most cases, you can still reinstall OS X using an external drive containing the installer. Professional help is advised if all DIY steps fail to get a normal recovery system working again. Sticking to best practices like regular backups and disk maintenance can prevent many recovery partition issues from occurring in the first place.