this is Disney's live-action spin on their old
Fantasia segment.   is nothing sacred?!   well, Mickey fans can rest easy; this has nothing to do with the beloved Mickey-battles-the-flood short, and everything to do with capitalizing on the famous name.   think
National Treasure meets Harry Potter.   Alfred Molina is likely to be a great big PLUS for this film, as he's usually pretty fantastic, and he gets to play a villain here.
this film's premise is similar to
The Vampire's Assistant
(trailer & clips
here), the first film adaptation of Darren Shan's
Vampire Blood trilogy
(the first of 4 trilogies in his fictionally biographical
Saga of Darren Shan
arc).  
Assistant had some great story elements, a lot of humor, and occasionally stellar special effects work; it was entertaining, but short of outstanding.   not having read the books, i can't comment on them personally, but i gather J.K. Rowling liked them.
Apprentice looks like it had a lot higher budget- your typical Disney summer blockbuster / family-oriented action-adventure film.   i was skeptical but, judging by the trailer, this could be fun.