It seems Apple is struggling to keep stock of the MacBook Pro with Retina display, as estimated delivery times for new orders have been delayed for the second time this week. On Tuesday, Apple's online store listed expected shipment arrivals as 2 to 3 weeks, but now, new orders are being pushed back to 3 to 4 weeks. Customers may be able to forego the delay by arranging for an in-store pickup, though the option is dependent on local retail availability. Those interested in Apple's newly refreshed MacBook Air and standard MacBook Pro, on the other hand, will have no delay.