Can't enter password in Disk Utility to Mount Encrypted Drive

What happened during the attempted upgrade to Mojave? How far did the install process get?

Within Disk Utility click on "View" and select "Show all devices". The physical drive should appear in the left pane of Disk Utility. Try running First Aid on the physical drive.

Were you able to complete the setup?

Did you get to a login screen?

Did it attempt to log you in?

I'm trying to understand exactly where the new Mojave installation stopped working.

Definitely try running First Aid on the physical drive as I suggested in case the drive's partition table needs repaired as that might be your only hope of unlocking Filevault.

Try an SMC reset and a PRAM reset (hold the PRAM reset for at least three chimes so it activates several times).

Try task switching to the Finder, then go back to Disk Utility. Maybe try pressing the Tab key to see if it might cycle focus around to the password field. Have you quit Disk Utility and then relaunched it? Have you clicked "Cancel" on the password box then try to unlocking the volume again?

Did you ever change the user account password before the Mojave upgrade? Even if it occurred many years ago? Is there more than one user account on this laptop?

For me I finished the upgrade to Mojave but at first start it wanted to install another update and after that it booted with the forbidden sign.

During the Mojave upgrade I was asked to add a password as this machine didn’t have it.

I can’t tab to the checkbox and a disk clone to an external disk and connected to a different machine experiences the same dialogue problem.

What happens when you try to boot the computer normally?

I got the prohibitory sign after a failed update to mojav. I was on 10.8 they said. Now what’s happening is we get to the recovery operation. First aid checks out fine. Even Genius Bar said test came back great. Just when you select to re enter the password to download the software the box will not let me type on the password. Had a authorized dealer to try and it did the same on different computers.

I asked the same question here: https://apple.stackexchange.com/questions/367321/unlocking-apfs-volume-window-doesnt-accept-input

Did you find a solution? I’m going through the same but not getting clear answers.

Far enough where it rebooted and came back up with the mojav screen and function to complete set up. Ran the test everything was fine they say.

i honestly can’t recall. I just know it did everything to install then reboot took me to finish set up froze and boom I have this problem.

What I don’t understand is why it’s greyed our after taking the password to do the update and log in. But I can’t get passed it.