Skype disappointed scores of holiday revelers over the Christmas season thanks to a significant outage that prevented distant loved ones from chatting via webcam from Dec. 23 to 25.

Now Skype CIO Lars Rabbe has an explanation for the poorly planned outage: Microsoft Windows.

According to a blog posting from Rabbe:

“On Wednesday, Dec. 22, a cluster of support servers responsible for offline instant messaging became overloaded. As a result of this overload, some Skype clients received delayed responses from the overloaded servers. In a version of the Skype for Windows client (version 5.0.0152), the delayed responses from the overloaded servers were not properly processed, causing Windows clients running the affected version to crash.

“Users running either the latest Skype for Windows (version 5.0.0.156), older versions of Skype for Windows (4.0 versions), Skype for Mac, Skype for iPhone, Skype on your TV, and Skype Connect or Skype Manager for enterprises were not affected by this initial problem.

“However, around 50 percent of all Skype users globally were running the 5.0.0.152 version of Skype for Windows, and the crashes caused approximately 40 percent of those clients to fail. These clients included 25 to 30 percent of the publicly available supernodes, also failed as a result of this problem.”

Skype wasn’t the only tech titan to dampen the holiday season this year. Beginning at 8 p.m. on Sunday, Nov. 28, Comcast customers up and down the right coast found themselves without Internet connectivity. Comcast, which initially reported that it had no idea what caused the outage, now attributes it to “server problems.” Affected states included Massachusetts, Connecticut, New York, Maryland, Virginia, New Hampshire and Washington, D.C. Interestingly enough, the outages appeared to affect only high-speed cable Internet service, and did not knock out the company's digital TV and VoIP telephone offerings.