The makers of the Windows operating system could be seeking new office windows. Microsoft has hit the market with an RFP, seeking office space of up to 50k SF in North Fulton.

It's a deal that could potentially mean the longtime office at Sanctuary Park moves to new digs. Sources say Microsoft has just hit the market, still has more than a year left on its current lease, and just recently tapped Colliers International's Drew Levine and Jeff Kelley in the search. And sources say a renewal—which it's done twice already at The Falls at Sanctuary Park—is still a possibility. But the company is open to other projects, including possibly anchoring Hines Interests' office component at Avalon.

This is the second big RFP secured by Colliers in recent weeks. The firm also has been tapped by RaceTrac Petroleum for its office search. As we previously reported first here, RaceTrac is eyeing a replacement for its 200k SF HQ at Cumberland Center IV as it continues to experience a huge corporate growth spurt.