When the word that introduces a clause, the subject of the clause may not follow immediately; in such a case, the writer is often tempted to repeat the word that later in the sentence. Consider the following:
Note the doubling of that. The author begins a that clause, then interrupts it with an if clause (if the software . . . ), delaying the grammatical subject of the that clause, a copy. The separation is awkward but grammatically acceptable. The problem lies in the second that, which is unnecessary and should be eliminated.
The awkward separation of that and a copy that led the writer to commit this error is easily remedied by beginning the sentence with the if clause: