Net phone firm Skype says its service is up and running again after three days
of "unprecedented" disruption.
The problems with the service began on 16 August and stopped millions of people
logging in and making calls.
Skype said the ongoing disruption was caused by a network software upgrade that
went awry.
Despite Skype's claim to have fixed the problems some subscribers reported that
they had trouble making calls throughout the weekend.
Flash flood
In a statement posted on its website, Skype said the widespread outage began
after Skype's servers around the world re-started following a software upgrade
to user's computers.
The knock-on effect was that an unusually high number of people tried to log on
to the system at once and the Skype network could not cope.
To make matters worse, the scale of the failure exposed a previously unknown
bug in the algorithm that should have helped the Skype network recover quickly.
The statement said: "as a result of this disruption, Skype was unavailable to
the majority of its users for approximately two days."
It added: "...we'd like to apologise and thank you. Precisely in that order."
The company categorically denied that any malicious elements were behind the
prolonged disruption.
Exact numbers of Skype users are hard to come by but the company claims that
its software has been downloaded about 200 million times and it is thought
about 50 million people regularly use it.
Sites and blogs that watch Skype reported problems in many different countries
including the US, Canada, Brazil, Germany and Finland.
Although Skype said the service was back to normal for the majority of its
users, over the weekend of 18-19 August many subscribers said they were still
having problems.
Some said calls cut out unexpectedly and others struggled to get it working.
Many bloggers inconvenienced by the outage wondered if Skype was planning to
refund them for all the calls they had to re-direct to other, usually more
expensive, phone numbers during the period of disruption.