Lost login id's

Hello,

I have lost 2 of the log in account on start up on my imac.
normal there are 3. mine, wife, daughter.

but as of this afternoon it only shows mine. and not the other two.

i had a smilar problem a month ago. but rather than showing just mine it only showed an administrator account requiring a password which i did not know.

and could not access the computer. only way get around this was boot from OS disc then restore using time machine. but as this takes 20+ hours would prfer to know why this happens and a way to fix it.

any ideas?

20 hours

Are you sure, it only took me a couple of hours to restore a Mac with a failed hard disk back to its 2 accounts, mine and the missus

2tb hard drive with 1.8gb of things, music, HD movies photos, etc.

it starts off saying 43 hours but 20 is an improvement. oh and its backing up from a 2TB USB 2 External hard drive.