The creators of the online Potter portal said on Friday that the launch of an e-book store has been pushed back to next year.
The seven Harry Potter books had been due to go on sale in October, exclusively through the Pottermore website.
The site is a combination of virtual encyclopaedia, role-playing game and online community for fans of author J.K. Rowling's boy wizard. It launched in July and is so far accessible to 1 million registered users chosen through an online competition.
In a blog posting on the site, Pottermore management said registration would be open to everyone from the end of October, and the online store would open in "the first half of 2012".
The posting said use of the site so far had been "phenomenal", and the delay would "allow us to focus on our first priority: opening Pottermore to as many people as possible and making the experience as good as it can be".