My keyboard does not work when trying to login to my MacBook Pro

cay145 wrote:

I do that whenever it’s not working and it will allow me to login. However it’s only a temporary fix as the problem occurs the next time I need to log in and I do not like having to completely reset the NVRAM/PRAM every time I want to use my computer

Boot into Recovery (Command R) and from the dropdown menu: Utilities>  Disk Utility> run the First Aid on your Macintosh HD. If errors are found and repaired, run again until no errors reported.

Latest Mojave Recovery a bit different—

How to reinstall macOS from macOS Recovery: https://support.apple.com/en-us/HT204904

High Sierra 

Recovery  http://support.apple.com/kb/HT4718

  To trouble shoot further you can:

  Try a SafeBoot https://support.apple.com/en-us/HT201262

  Takes noticeable longer to get to the login screen, does a 5-15 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache,  etc.  When you get to the login screen, reboot and test.

This test will tell you if third party interference; extensions etc are not loaded in safe boot mode. 

  Test issue in another user (or guest user) account  https://support.apple.com/en-us/HT204443

This will tell you if it a universal issue or isolated to your user/admin account. 

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"—

https://www.apple.com/retail/geniusbar/

Outside the USA

https://locate.apple.com/country

Did you Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379