Twitter Says Apple Mobile Software Bug Caused It to Lose Millions of Users

The Twitter iPhone app.
Photographer: Andrew Harrer/Bloomberg

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By Sarah Frier and Tim Higgins

February 5, 2015 at 11:23 PM UTC

Updated on

February 6, 2015 at 10:13 AM UTC

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Twitter Inc., which posted disappointing fourth-quarter user growth, gave a surprising reason for the slowdown: Apple Inc.’s new mobile software.

The San Francisco-based company said Apple’s September rollout of iOS 8, the iPhone maker’s new mobile operating system, cost it 4 million new users for integration-related reasons. There was an “unforeseen bug in the release of iOS 8 as it related to Twitter,” Chief Executive Officer Dick Costolo said on a conference call Thursday.