Skype has moved quickly to fix problems that hit users around the world.
Many people started to report that they had problems making calls via the net-based phone system earlier today.
The problem did not seem confined to one group, with users on machines running Windows, OS X and Linux all reporting trouble.
Skype issued advice about how to get its service going, while it worked on a permanent fix.
Messages about problems getting Skype to start up began to be posted on social networking sites such as Twitter soon after it sent out a software update.
The update made it impossible for many people to sign in and make calls.
Skype posted an update about the outage to its blog, saying a "small number" of people have had problems and detailing how to get the service running again.
Skype said the problem predominantly affected Windows users, but it also posted advice for OS X and Linux users. All the solutions revolved around the deletion of a file called "shared.xml".
It also said it had identified the problem and would issue a fix "in the next few hours".
The large number of people turning to the Skype.com website for advice and information also briefly knocked that offline.
The outage comes two weeks after Microsoft confirmed that it was paying $8.5bn (£5.2bn) for the firm.
The swift response stands in contrast to the speed with which problems that plagued Skype in December 2010 were solved. That led to the service being offline for almost two days.
An investigation showed that a software bug and overloaded servers were responsible for that incident.