Now, there is a problem with how the application handles "Today's Crossword" from the NYT (but not the archives)... the current puzzle has the solution scrambled (it's part of the .puz file format specification)
Using a locked puzzle Sometimes a puzzle will be locked so that the answers are unavailable. Unfortunately, Xword's support for locked puzzles is somewhat flaky. When using a locked puzzle, you should not click on the "Check" or "Solve" buttons, since they will give incorrect information. However, you can still use Xword to enter answers for a locked puzzle. Later, when an unlocked version of the puzzle is released (usually the next day), open it using Xword. When asked, choose to continue where you left off. Now you can use the "Check" and "Solve" buttons to see how well you did. (Sometimes crosswords will come with a four-digit code to unlock a locked puzzle file. This code is not needed by Xword.)