Initial keypresses not registering during macOS Tahoe login

Starting with macOS 26 Tahoe, FileVault is enabled by default. All Macs that can run Tahoe or later have the internal storage encrypted at the hardware level. FileVault increases security by incorporating the user's login password into the cryptographic key. Practically, that means that after a reboot/startup and before you enter your login password, the Mac is not able to access user account settings or the internet. 

When FileVault is enabled, a Mac boots by stopping at an early pre-boot authentication screen to decrypt the startup disk before loading the main operating system or network services. 

Changes to the boot sequence with FileVault enabled:

• Early Password Prompt: You see a special FileVault unlock screen immediately after the hardware loads, before normal user services or Wi-Fi connections start.
• No Network Access Yet: Because network stacks require user-space services to run, the Mac cannot connect to standard Wi-Fi networks until you enter your password to unlock the drive.
• Decryption Unlocks the OS: Entering your account password provides the key to decrypt the drive, allowing the Mac to hand off control and finish booting into the standard macOS interface

You can disable FileVault in System Settings > Privacy & Security > FileVault (near the bottom of the settings pane) – click the setting and toggle FileVault off.

With FileVault off, the boot sequence will be 'normal' because user settings and network access will be available prior to entering the login password. Keep in mind that Apple enables FileVault by default for a good reason – to protect your Mac. If someone gains physical access to your Mac and you do not have FileVault enabled, it is a simple matter for them to access the data stored on your internal drive, either by changing your login password or via the Recovery OS. With FileVault enabled, your login password is required to access your internal storage. 

Given the enhanced security, I recommend leaving/turning FileVault on. There is no ‘penalty’ in terms of performance, the data encryption/decryption is handled by dedicated hardware and is happening regardless of FileVault status, since that merely changes the key used for encryption. 

More info on FileVault:

Protect data on your Mac with FileVault – Apple Support

Intro to FileVault – Apple Support

In terms of troubleshooting (especially if you have FileVault disabled already), see if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, and also disables 3rd party extensions that may cause problems.

Start up your Mac in safe mode - Apple Support

If that does not correct the issue, test in a new user account. A newly-created user account will have all settings at default, and if the issue does not occur in that new account then it provides guidance on what may need to be changed to correct the issue.

Add a user or group on Mac - Apple Support

Once the testing is complete, the new account can easily be deleted.

Delete a user or group on Mac – Apple Support

Those steps will help to isolate the problem.

The quickest workaround is behavioral. When the login screen or an app password dialog box pops up:

• Do not start typing immediately.
• Wait 1 to 2 seconds for the password text field to fully initialize, animate, and display a flashing cursor.
• If you type immediately, the operating system registers the keys but drops them while it opens the secure input tunnel, corrupting the beginning of your password entry.