The Quickest Fox in the East
Microsoft Word from 97 to 2003 (and some Mac Word versions) — 10 characters

No repetitions, but doesn't quite match specs - 10 characters:

=rand(2,1)


Output:

The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.


Matches specs, other than capitalization and punctuation, one repetition - 10 characters:

=rand(1,1)


Output:

The quick brown fox jumps over the lazy dog.


Newer versions of Microsoft Word use =rand.old(1,1) which duplicates d and 1.

There might be a way to use a field {=SUM(3,-2)} as input to rand() but my installation is having issues with fields -- namely, they're not working...

"Bob" has confirmed that {=SUM(3,-2)} (with some difficulty) can be used to replace the first 1, but = is repeated...

=rand({=SUM(3,-2)},1)


Provided you get Word to update SUM first, the output is:

The quick brown fox jumps over the lazy dog.