achloes
I came across the following on the Veritas Prep Sentence Correction book, and I'm hoping for one of the experts to shed some light on why the first option is incorrect.
Personally, I feel that both are perfectly logical and could be used interchangeably.
Incorrect: Software X crashes more often than Software J. Correct: Software X crashes more often than does Software J.I also came across a similar question on my GMAT exam in November that tested this exact concept so I'd like to put this confusion to bed before my next attempt!
Many thanks in advance

Either is correct!
This gets tricky. With comparisons, the difficulty often lies in what words ARE left out and which words CAN BE left out.
In your example, the only choices are:
Software X crashes more often than Software Y [crashes].
Software X crashes more often than does Software Y [crash].
Either is acceptable, structurally.
But take these sentences (with apologies to Scottie Pippin fans):
Michael Jordan was better at basketball than Scottie Pippin.
Michael Jordan was better at basketball than baseball.
We, as humans, understand perfectly the meaning of both sentences, but notice they are STRUCTURALLY identical...
The first one we know means:
Michael Jordan was better at basketball than Scottie Pippin [was good at basketball].
and the second means:
Michael Jordan was better at basketball than [he was at] baseball.
But how is a ROBOT supposed to know that? Why can't a COMPUTER interpret the first as:
Michael Jordan was better at basketball than [he was at] Scottie Pippin.
and the second as:
Michael Jordan was better at basketball than baseball [was good at basketball].
These interpretations don't make since to us... How can Michael Jordon be good at Scottie Pippin? Scottie Pippin isn't a game. How can baseball be good at basketball? Baseball... doesn't play basketball! So, since the COMPUTER is confused about which we mean and the ambiguous structure allows illogical sentences, we need to clarify our original sentences:
Michael Jordan was better at basketball than was Scottie Pippin.
Michael Jordan was better at basketball than at baseball.
These allow ONLY the interpretations:
Michael Jordan was better at basketball than was Scottie Pippin [good at basketball].
Michael Jordan was better at basketball than [he was] at baseball.