The iconic internet calling and chat service it bought almost 14 years ago.
Microsoft said there were more than 300 million monthly Skype users in 2016.
But its daily users count had dwindled to 36 million in 2023.
Once a byword for digital calls that bypassed long-distance charges, Skype was surpassed in recent years by smartphones.
When Microsoft tried to stretch the Skype brand into the workplace, it lost out to Slack Technologies Inc.
Microsoft's response was to start from scratch and build teams.
Microsoft, which also saw its acquisition of Nokia Oyj's mobile phone business end in failure, is far from alone in encountering rejection by a fickle consumer market