Employees made redundant by Microsoft are being asked to repay cash after the firm claimed their severance amounts were too high.
It is also believed some were underpaid, through the accounting mistakes made by Microsoft's human resources department in the US.
Microsoft made 1,400 staff redundant last month in response to the global recession, and the mistakes in the final pay packets of an undisclosed number of staff were uncovered by TechCrunch.
A Microsoft letter to those it says were overpaid reads: "An inadvertent administrative error occurred that resulted in an overpayment in severance pay by Microsoft. We ask that you repay the overpayment and sincerely apologise for any inconvenience to you."