MacBook sales traditionally surge in the third quarter thanks to back-to-school sales, however a new report suggests that Q3 shipments of Apple’s laptops this year likely won’t be as strong as they have been in years past. According to Digitimes, MacBook shipments are expected to reach 4 million units in the third quarter, up 10% sequentially but down year-over-year. Digitimes notes that MacBook sales have averaged 5 million to 6 million units during the third quarter in previous years. Sales of the 13-inch MacBook Pro are said to have fallen short of Apple’s expectations, forcing the company to clear inventories and suspended new build orders in the first half of 2013. Apple has reportedly “taken stricter control of its supply chain,” and even introduced new suppliers in an effort to pressure its existing partners.