Microsoft has suspicions that an ex-employee retained strategic data after he left the firm for a position at rival Salesforce.com.

In an amended court motion, filed with a Washington State Superior Court on Thursday, Microsoft alleged that Matt Miszewski lied about retaining over 600MB of proprietary information after he left the company, according to reports.

"[The data] would be highly valuable to Microsoft's competitors, including Salesforce.com," Microsoft said in the motion, according to Computerworld, "both in terms of capitalizing on Microsoft's efforts to prepare these materials, as well as revealing in detail Microsoft's own competitive strategies."

Upon his resignation on 31 December Miszewski told Microsoft he had taken purely personal items with him, Microsoft said in the motion.

Read more of "Microsoft accuses former employee of cloud data theft" at ZDNet UK.