A lost document can make an existing person temporarily impossible to recognize officially.

Officially, you are your paperwork. Lose the document that links you to the record and you become someone the system cannot confirm, even though nothing about you has changed and everyone who knows you would vouch for it. Existence and recognition turn out to be separate things, and only one of them can be misplaced in a move. The gap between them can last weeks and cost a great deal.

Keep copies, in more than one place, of the few documents that everything else hangs from. If you are in the gap now, look for the one record that regenerates the others and start there rather than everywhere. And be patient with people stuck in this position, because the problem is not carelessness, it is a system with a single point of failure.