Microsoft Corp reported a dip in quarterly sales of its core Windows operating system, mirroring a recent downturn in personal computers and sending its shares down slightly.

Microsoft’s shares fell 2 per cent to $26.15 in after-hours trading following the earnings report yesterday.

Microsoft reported a 31 per cent increase in fiscal third-quarter net profit, reporting $5.2 billion, or 61 cents per share, compared with $4 billion, or 45 cents per share, in the year-ago quarter. Five cents per share of that profit was attributed to a one-time tax benefit.