A few weeks after launching the first wide-scale layoffs in its history, Microsoft Corp. admits it flubbed a key part of the plan.

First Microsoft realized that an administrative glitch caused it to pay more severance than intended to some laid-off employees. The company's response: It asked the ex-workers for the money back.

But when one of Microsoft's letters seeking repayment surfaced on the web on Saturday, the situation turned embarrassing. On Monday, the company reversed course and said the laid-off workers could keep the extra payouts.

Lisa Brummel, Microsoft's senior vice-president for human resources, said the letters were mailed to 25 of the 1,400 people let go in January. Most of the cheques were off by about $4,000 to $5,000, she said.

Brummel said she learned of the letters over the weekend after one appeared on the technology blog TechCrunch.

"I decided it didn't quite feel right," she said in an interview.

The executive called most of the 25 laid-off employees Monday to personally tell them Microsoft would not seek repayment after all.

Redmond, Wash.-based Microsoft also gave about 20 employees too little severance. When the company noticed its mistake, it sent cheques and explanations to those people, she said.

Brummel called the glitch a clerical error, and said that at some point in the process of calculating severance packages, communicating with employees and cutting cheques, "we had payments misaligned with people's names."

With the recession biting into sales of Microsoft's core Office and Windows software, the company said in January it would let up to 5,000 of its 94,000 employees go, the only mass layoff in its 34-year history.

Microsoft remains profitable, however, and has a cash hoard of nearly $21 billion.