Microsoft said its quarterly profit fell as Office software sales slowed ahead of a new launch, offseting a solid start for its new Windows 8 operating system.

Profit at the world’s largest software company slid to $US6.4 billion ($A1.6 billion), or 76 cents a share, in the fiscal second quarter, from $US6.6 billion, or 78 cents a share, in the year-ago quarter.

Wall Street had expected 75 cents per share, on average, according to Thomson Reuters.

Overall sales rose 3 per cent to $US21.5 billion, Microsoft said, in line with analysts’ estimates.

With the loss of some deferred revenue to account for discounted upgrades to new software, Office revenue fell about 10 per cent to $US5.7 billion, which is not unusual ahead of a new launch, expected next week.

Windows sales, which included some deferred revenue from the launch of Windows 8 last October, jumped 24 percent to $5.9 billion.

Microsoft said it has sold more than 60 million Windows 8 licenses since launch, a solid but unspectacular start for its latest operating system.

Microsoft shares fell slightly in after-hours trading.

Reuters