Microsoft started selling its Surface Pro tablet on Saturday, and quickly exhausted its supply of the 128GB configuration.
While the less expensive 64GB device was also listed as out of stock Saturday on Microsoft's online store, by Sunday it was again available.
The company acknowledged the outages.
"We're working with our retail partners who are currently out of stock of the 128GB Surface Pro to replenish supplies as quickly as possible," said Panos Panay, general manager for Microsoft's Surface line, in a Saturday blog post. "Our priority is to ensure that every customer gets their new Surface Pro as soon as possible."
Numerous online reports noted the shortages, saying that some Microsoft retail stores sported Apple-esque lines on Saturday and that many Best Buy and Staples locations -- Microsoft's retail partners for the Surface in the U.S. -- had single-digit supplies that in some cases were claimed earlier in the week.
Microsoft is selling the Surface Pro in the U.S. through its online e-mart, its approximately 70 retail outlets, and the Best Buy and Staples chains.
The device, which runs Windows 8 and is powered by an Intel processor, sells for $899 in a 64GB storage configuration, and for $999 with 128GB. Keyboard-cover accessories -- the Touch Cover and Type Cover -- sell separately for $120 and $130, respectively.
On Sunday, Best Buy's website said that it could not ship either model, but customers should instead check local stores. A spot check of several locations, however, showed that none had the Surface Pro in stock.
The situation was similar at Staples' e-store, although several individual stores reported having some 64GB Surface Pros available.
Microsoft did not release sales numbers for opening day, keeping with its practice of remaining mum on the progress of the Surface line. The Surface RT, a tablet that runs the limited operating system Windows RT, launched last October, but Microsoft thus far has declined to comment on sales.
Some observers interpreted the quick sell-out of the 128GB device as a sign that early buyers, at least, were evaluating the Surface Pro as a notebook replacement first, and as a tablet second.
Microsoft has been pitching the Surface Pro as suitable for both notebook- and tablet-like tasks, with one top Windows executive recently comparing its price to a double purchase of Apple's MacBook Air laptop and iPad tablet.
Another interpretation could be that buyers were turned off by the 64GB model's relatively paltry amount of storage space available for applications and user content.
Microsoft added to the confusion over the 64GB Pro's customer-available storage space by first reporting that as 23GB, which quickly attracted criticism. Later, the company said that that number was inaccurate, and that the available space was actually 29GB.
