Some Skype users have been reporting that the update that Skype issued to fix a corruption that affected users' systems, more specifically, an XML file, has not solved the issue.
The VoIP provider urges users to make sure that there are no Skype processes running in the background which might prevent the update from being successful.
More specifically, Jennifer Caukin from Skype suggests that users should "quit your existing Skype application, restart your computer, then begin performing the download". Closing down Skype normally leaves another executable file, SkypePM.exe in the background. Users also need to be careful to disable Skype's ability to launch itself when Windows starts.
A Mac update has also been released for Mac users which resolves a startup crash whose origins stem from the same shared.xml file that caused havoc on the PC platform.
Skype has not since reached the 30 million concurrent users level that it reached back in March 2011. It is likely that a small but significant portion of its users have been facing issues when installing the update. Only two downtimes over the last four years - one in December 2010 and the other in August 2007 - have had such a large impact on the registered user base.