Users of Skype in Asia and parts of Europe were able to log on and use the free phone service Friday, nearly 24 hours after a software bug hit the popular program.
The company, a division of online auction company eBay Inc., said that while some of its estimated 220 million users had reported successfully connecting, others still were unable to do so.
"We're on the road to recovery," the company said on its Heartbeat blog Friday morning. "Skype is stabilizing, but this process may continue throughout the day. An encouraging number of users can now use Skype once again. We know were not out of the woods yet, but we are in better shape now than we were yesterday."
The computer program lets its users make long-distance phone calls over the Internet.
The worldwide outage began early Thursday afternoon. Users from Vietnam to Brazil to Germany to the United States said they could not log on and make phone calls or send instant messages.
Skype said late Thursday that the issue was a problem with its software. It said it still hopes full service will resume Friday.
Skype has 5 million to 6 million users usually online at given time. In January, Skype reported that it had counted 9 million users online at one time.
Skype urged users to allow the program to continue running and said they would automatically be logged on when the problem is resolved.
Skype, founded by Niklas Zennstrom and Janus Friis, uses peer-to-peer technology to connect phone calls, instant messages and videos between its users. It runs on a variety of operating systems, including Windows, Mac OS X, PocketPC and Linux.
Besides computer-to-computer calls, Skype users can also use the program to connect to cell phones and traditional land line telephones.
The company was acquired by eBay in October 2005 for about $2.1 billion.