What does "[Update Needed]" mean when attempting to boot from an encrypted backup?

Solution 1:

Try this: https://discussions.apple.com/thread/3321886?start=0&tstart=0

• To begin, make a backup.
• Disable FileVault.
• Check for updates again.
• Apply update if possible.
• Boot into recovery mode by holding Command ⌘->kbd>R at startup.
• Run Repair Disk Permissions in Disk Utility.
• Enable FileVault again.

Solution 2:

[Update Needed]

This may also appear on an Apple_Boot slice (partition) that is not updated according to the list of users who are enabled for FileVault 2.

Visualising changes to an Apple_Boot slice

This first screenshot, from Mountain Lion, shows changes to the file system after using the Startup Disk pane of System Preferences – without a change of preference.

Critically:

• changes were whilst booted from a startup volume named OS
• changes were to the file system on a separate volume named Boot OS X – on the Apple_Boot slice.

The two shots below are more relevant. Additional changes to the file system after using the Security & Privacy pane, to enable unlocking by an existing user who was previously without that ability:

There, most changes were probably made by corestoragehelperd and/or a related process.

SuperDuper! backups to an encrypted logical volume (LV), and booting

I guess that SuperDuper! does not write – to a non-encrypted area – what's required for EfiLoginUI to present a recognisable list of named users.

Time Machine backups to an encrypted LV, and booting

When EfiLoginUI prompts for a passphrase:

• the encrypted LV is not yet unlocked.

Without that LV, I don't know which area of a disk is used for EfiLoginUI to present its dialogue, but generally …

Defocusing from SuperDuper! and from Time Machine

This answer may help readers to understand what occurs when updates are made to the parts of a file system that will be used by EfiLoginUI.

Side note

In some cases, interaction with the [Update Needed] interface may present a password hint:

The user Graphics resources appears to be invalid

A photograph of Lion: