Track pad failure signing in.

If you have user login accounts shown on the screen, then you don't need to use the Trackpad at all to log in. Just follow my earlier instructions to type the first character of one of the user account names followed by pressing the "Return" key which will select that user account and provide you with the password prompt for it. Use the "Return" key to submit the password. I don't know what you can really do once you log in though if you don't have a working trackpad or mouse. I've done this multiple times. Perhaps it may even be possible to use the arrow keys or Tab key to move between the listed users, but I've never tried it.

I would be concerned whether the battery may be swelling and pressing against the Trackpad preventing its movement. Does the laptop sit firmly on a flat surface or does it wobble a bit which would indicate a swollen battery? Another common issue is liquid residue and crumbs have gotten stuck beside or beneath the trackpad causing the physical movement to become restricted. Of course there is always a chance the actual micro switch on the Tracpad is failing, but this is extremely rare in my own personal experience.

chuckdemin wrote:

Is there a way to sign in to my late 2013 MacBook Pro without having to select the user then click the trackpad? My trackpad click function is barely functioning and I don't dare turn the computer off for fear of not being able to log back in, so I'm keeping in in sleep mode when not in use.

Connect an external trackpad and /or keyboard if necessary

Magic Trackpad - White Multi-Touch Surface - Apple

Magic Trackpad - Black Multi-Touch Surface - Apple

Set up your Magic Keyboard, Magic Mouse, or ... - Apple Support

Apple Magic Trackpad 2 Silver MJ2R2LL/A - Best Buy

Apple Magic Trackpad 2 (Wireless, Rechargable) - Silver-Amazon

Apple Magic Trackpad 2 - Walmart.com

You can type the first character of a user account name followed by pressing the "Return" key. Then you can type the password and submit it by pressing the "Return" key. This assumes you have a login icon when you boot the Mac. If you are presented only with blank fields because you need to enter the user name manually, then you may need to try pressing the Tab key to see if it will highlight the user name field, then press Tab key again to move to the password field, followed by pressing the "Return" key to submit the information.

An external mouse as suggested by @leroydouglas would be the best & safest option though.

You may want to try a PRAM Reset (hold the PRAM Reset for at least three chimes if possible) to see if it helps with the Tracpad issue. It also never hurts to try an SMC Reset as well.