"macbook pro 2019 keyboard and trackpad not working: Hi all, when I turn on my laptop and reach the login page, I'm unable to type my password or click using the trackpad. However, I can still move the cursor. Has anyone encountered this issue before? I have tried to use external keyboard and mouse on it but still it won't work."
-------
Troubleshooting Mac TrackPad:
A. Reset the SMC and your NVRAM:
(Applies to macOS-Installed Macs only). Sometimes when changes are made to the system(i.e. updates), system configurations (i.e. for keyboard) become manipulated, technically. So, reset the SMC and NVRAM.
B. Boot into Safe Mode:
When you boot into Safe Mode, items load by default, with certain settings and caches set aside. So, hold down the shift key upon boot. See what happens then.
C. Single-Out this User:
What happens when you create a new Administrator user? do you still get this error? If not, then it it like an issue with the configurations of the current user. If so, then it is an issue of the macOS, in which case, you'd need to reinstall it.
D. Restore from a Backup:
Any recent Backups prior to this?: If you backed up your Mac prior to updating it then, restore form it. Sometimes, an update can fail due to power issues, or losing connection to Apple's servers. So, know to always back up your Mac prior to making any major changes to it, successfully as au update. In doing so, you with have something to restore store your Mac from from, should anything go wrong with the upgrade.
E. Reinstalling the macOS:
Another option would be to reinstall the macOS. Perhaps an install was not 100% successful? Sometimes, when major changes are made to your Mac(i.e. update installations), system settings (i.e. for the fan) become manipulated, technically. So, when reinstalling, nothing would be deleted. It's just that items that have become corrupted or deleted, would be replaced or reinstalled back to where they should be. Go Here: How to Reinstall macOS from macOS Recovery - Apple Support. Important: Be certain you back up your Mac prior to the installation, as I mentioned in C.