Safe mode , smc , NVRAM/ PRAM are the basic troubleshooting steps , if they don't work its always wiser to erase the hard drive and reinstall the os see this article macOS Sierra: Erase and reinstall macOS
I start up in what I think is safe mode (press the shift key down while starting computer). The grey Apple logo comes up and it goes to the login screen. I login to my account and the computer tries to “load”, but it never makes it to
I had problems on my Mac for a couple months - would have to restart it in order to log in. The login page would show a little orange check next to my icon/name and if I tried putting in my password, it would just hang up and the mouse wouldn't even respond. I had chatted and spoke with Apple Support, but they didn't recognize the problem. Having to restart constantly if I was away from the computer for any length of time was so disrupting, I didn't even notice that I also was having to put my password in twice after I was able to log in. Once I figured that out, searched and found this solution. I used the second option - it took about a day to de-crypt and re-crypt but it fixed it! You can still use your computer while it's "crypting". Good luck!
https://www.macissues.com/2015/03/31/fix-double-login-prompts-on-your-mac/
To the load screen. I have let it run for up to 8 hours straight, but it never goes to the home screen.
Login problems
