Triple-click the line below to select it:
/System/Library/CoreServices/Directory Utility.app
Rght-click or control-click the highlighted text and select
Services ▹ Open
from the contextual menu.* The application Directory Utility will open.
In the Directory Utility window, click the lock icon and authenticate. Select the Directory Editor tool in the toolbar. Select Users from the Viewing menu in the toolbar, if not already selected. Select the affected user account in the list. On the right is a list of properties and values. Select the property "HomeDirectory" and delete it by clicking the minus-sign icon directly below the property list. There are two such icons in the window. You want the one on the right, not the one on the left.
CAUTION: Do not click the minus-sign icon on the left, below the user list.
Then click the Save button in the lower right corner of the window. Quit Directory Utility.
CAUTION: There is no "undo" in Directory Utility. If you make a mistake and delete something in the Directory Editor that should not have been deleted, restore your whole system from a backup and start over. I have no other help to offer in that case.
Try again to log in as the affected user. If you can log in, you should find a file in the home folder with the name of the user and the filename extension "sparseimage" or "sparsebundle". Double-click that file. A disk image should open. Copy your files from that disk image to restore them.
I strongly suggest that you deactivate legacy FileVault in the Security & Privacy preference pane, then log out and log back in. Consider activating FileVault 2 if you want that kind of security.
*If you don't see the contextual menu item, copy the selected text to the Clipboard (command-C). Open a TextEdit window and paste into it (command-V). Select the line you just pasted and continue as above.
