Software engineer Pratik Pandey was driven to death by the 'unbearable stress' of working for Microsoft, his grieving mom has told the Daily Mail.

The 35-year-old was toiling until 3am to hit targets and impress bosses ahead of a crucial performance review, according to his shattered family.

He had no obvious medical problems, but his parents became so worried they urged him to consider quitting his coveted $200,000-per-year job for the sake of his health.

The high-flier was found slumped face down in a courtyard at Microsoft's futuristic campus in Mountain View, California, in the early hours of August 20.

His loved ones from the central Indian city of Indore will have to wait 90 days for a formal cause of death but a provisional assessment suggested Pratik succumbed to a cardiac arrest.