Some of the beta testers for Microsoft's Windows Live Hotmail service are getting an increase in storage, but the extra capacity isn't always being introduced as smoothly as hoped.

The users will see from their storage meter that they now have 4 Gbytes of storage, up from 2 Gbytes before. But the extra storage might not actually have been assigned to their accounts yet, according to a company blog posting.

"This seems like putting the cart before the horse," the posting says. "The reason for this is that the storage upgrade is being gradually rolled across the universe and does not immediately change every account at the same time."

The problem should resolve itself as the upgrade continues over the next two weeks, Microsoft said. The expanded storage is only for "Hotmail Plus" customers who are beta testing Windows Live Hotmail, a revamped version of the company's Web email service.

Hotmail Plus customers pay $19.95 per year for a 2 Gbyte account and extras such as the ability to send 20 Mbyte attachments.

Microsoft's free Hotmail service offers 1-Gbyte of storage and a 10 Mbyte attachment limit. By comparison, Google's Gmail offers 2.6 Gbytes of storage for free and Yahoo's free email includes 1 Gbyte of storage.

Last month, Microsoft rolled out another feature upgrade, M10, for the Windows Live Hotmail beta, which is supposed to improve its speed and reliability.