on startup, cursor disappears in the password box only.

rubato117 wrote:

Unfortunately, neither rebooting worked. The same login screen came up but no cursor in the password box. Oddly it appears on the rest of the screen and is useful for shutting down and restarting. Thank you for your quick response.

If this is an Intel Mac—

Try resetting the SMC https://support.apple.com/en-us/HT201295

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

(get at least two-three rounds of the chimes when holding the NRAM Reset)

rubato117 wrote:

Cursor visible on startup page but disappears when I try to put it in the password box to add password.

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 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc.

See if you can Login here and test.

Reboot as normal and test. Caches get rebuilt automatically.