In emergency situations when You are not able to log into your Mac then to recover your existing data you need to boot into recovery mode to restore data as well as to restore Mac OS to old healthy running state. In general if you have older version of Mac you are using either OS X snow leopard or older then the recovery would be done by inserting CD or DVD to your Mac.
If you want to install reinstall Mac OS on your computer then you are required to read a blog here to fix mac OS could not be installed on your computer. But if you are not able to reboot your Mac into recovery then you can read best methods explained in the blog below to solve various issues in Mac OS to solve Mac recovery mode not working issue.
METHOD1: BOOT INTO RECOVERY
Step1: Shut down Mac by pressing shut down button after pressing Apple menu icon.
Step2: Now press and hold command with R button and press power button.
Step3: Mac utilities screen will open and after selecting appropriate option boot into recovery.
Step4: If you are not able to boot into recovery follow method2.
Also Read: How to Verify My Apple ID and Password?
METHOD2: USE TIME MACHINE
Step1: Restart Mac and select option on music tone and attach time machine.
Step2: Now wait till time machine load and after that select recovery drive to launch mac.
Step3: Wait for on screen commands and recover Mac OS on your computer.
Step4: After completion system will restart or use internet recovery.
METHOD3: USE INTERNET RECOVERY
Step1: Restart for Mac and on Music press Command + option + R until a globe is visible on screen.
Step2: Now select Wi-fi or lan connection and enter username and password.
Step3: Wait for 30 minutes now files would be automatically downloaded.
We are a team of certified professionals and working as an independent support to provide help for various issues in Mac operating system. You can get in touch with experts after dialing toll free number +1-888-488-2930 to get round the clock online help from Mac support phone number in USA and Canada.