Mac OS Installation Help - How did I resolved issues encountered

This post discusses the common issues that you may also face while setting up Mac OS in a Mac Book by wiping out data and trying to do a new installation.

Problem 01 : Ask for admin user credentials when try to restart on recovery mode.

Solution:  Restart the mac. when it shut off and powers back on, press and hold Command + R until you see the apple logo. Instead of going to recovery page directly, some mac versions ask for user credentials. If you doesn't know the credentials still you can do the installation. You can find erase mac option from the top menu of the page. Erase the mac and start the mac installation process.


Problem 02: File icon in the mac after erase the mac

Solution :  Restart the mac. when it shut off and powers back on, press and hold Options button until it shows the loading bar in the screen. From there you connect the internet and Select internet recovery option. It will recover the mac OS from the internet. After successfully recovered it allows you to access the reset utilities section and install the mac.

Problem 03 : When try to install mac os, at the beginning of the installation process it gives a popup message "The recovery server could not be contacted" and block the installation process.

Solution : This is due to time zone issue. You can fix this by providing a simple command in the Terminal window from utilities menu, which can be opened from the top menu. It solve above issue and allow to continue installation process.
ntpdate -u time.apple.com

Problem 04: When try to install mac os, at the beginning of the installation process it gives a popup with following message " To download and restore macOS, your computer's eligibility will be verified with apple"

After click on continue button to verify eligibility it will gives popup with following message. "UNTRUSTED_CERT_TITLE".

Solution:  This is also can solve by selecting the correct date time . Execute following command in terminal window.
ntpdate -u time.apple.com

The issues and solutions discussed here might help you to recover and setup Mac OS with a data wipe.