When your Mac can't load OS to boot up, you can reinstall OS in macOS Recovery Mode or use a bootable installer, if the macOS Recovery Mode not working, try Internet Recovery instead.
Without a working OS, the Mac can't function well. That's why it is a must to reinstall macOS when there are errors related to the OS. To reinstall macOS, it usually boots Mac into macOS Recovery Mode where you can reinstall macOS from the recovery partition. Unexpectedly, macOS Recovery Mode is not working.
When such an issue occurs, you can fix it with these methods:
- Check whether there is a recovery partition on your Mac. In 2010, OS X 10.7 Lion and macOS Recovery are released. Mac computers that run Mac OS X 10.6 Snow Leopard and earlier are not shipped with recovery partitions.
- Access macOS Recovery Mode in the correct way. The steps for entering macOS Recovery Mode vary from an Intel Mac to a Mac with Apple Silicon. Identify your Mac Model and boot up your Mac into macOS Recovery Mode correctly.
- Ensure the Command-R keys are working on Intel Mac. Either the Command key or the R key is defective, you can't get Mac into the standard recovery mode by pressing them. Check the keyboard by using these keys separately or check the connection for a Bluetooth keyboard to isolate Command-R not working.
In case the macOS Recovery Mode is still not working, try the following methods:
- Boot Mac into Internet Recovery.
- Use Fallback Recovery OS Mode on Apple Silicon Mac.
- Try DFU Mode on Mac running macOS 10.15.6 and later.
- Boot up from the Time Machine backup drive to restore.
- Reinstall macOS with a bootable installer.