In 2007, when the Dead Like Me movie was filming, Laura Harris had a full time job with Women's Murder Club. Apparently they couldn't work out a compromise that would let her appear in both.

You can see this implicitly on her IMDB page, but if you want an explicit statement, Yahoo Answers.

Mandy Patinkin presumably had a similar problem with Criminal Minds, but they knew about that beforehand and wrote him out of the script.

I'm not sure that I agree that Sarah Wynter is less attractive than Harris. The big problem with Wynter was that she simply wasn't the same kind of actress. That might have been fine for a first time casting, but in the kind of movie that this was, it really needed Daisy to be Daisy with the Daisy/Mason chemistry. And they didn't have it.

If they'd waited, both Harris and Patinkin would have been available, but then they might have lost Callum Blue or one of the Lasses. Or perhaps Christine Willes. Or the director.

In 2007, when the Dead Like Me movie was filming, Laura Harris had a full time job with Women's Murder Club. Apparently they couldn't work out a compromise that would let her appear in both.

You can see this implicitly on her IMDB page, but if you want an explicit statement, Yahoo Answers.

Mandy Patinkin presumably had a similar problem with Criminal Minds, but they knew about that beforehand and wrote him out of the script.

The big problem with Wynter was that she simply wasn't the same kind of actress. That might have been fine for a first time casting, but in the kind of movie that this was, it really needed Daisy to be Daisy with the Daisy/Mason chemistry. And they didn't have it.

If they'd waited, both Harris and Patinkin would have been available, but then they might have lost Callum Blue or one of the Lasses. Or perhaps Christine Willes. Or the director.