The number of workers at Microsoft that are now using Windows 10 as their primary operating system is well over 95%, a mark hit in less than 10 weeks after the company launched it on July 29. Microsoft recently posted a research study on their deployment of Windows 10 in their business that shows how their in-place update system made the transition for their roughly 120,000 employees much faster compared to older Windows updates.
When Windows 7 launched in 2009, it took a year for the update to reach 80% of Microsoft's employees, using a custom installation image. For Windows 8's launch in 2012, Microsoft created its own Windows Installer front-end application to speed up the update process for its workers, but it still took 8 months for the update to reach 85% of its team members.
The company piloted an in-place upgrade system for Windows 8.1's launch in 2013. The paper stated:
"Using the in-place upgrade eliminated the need to build a complex zero touch deployment image. Microsoft IT didn't have to create packages to deal with data migration or application reinstallation—everything just worked. The upgrade had a 97 percent success rate, and in the few instances that the upgrade failed, it simply rolled the computer back to its previous operating system. Microsoft IT saw a 35 percent reduction in help desk calls for setup, which was over the 10 percent reduction goal. Microsoft IT was able to deploy 95 percent of employees in three months by using the in-place upgrade and received user feedback that it was a great experience."
The in-place upgrade was also used for Windows 10 and it managed to complete the upgrade process for 85% of its employees in just four weeks and 95% inside of 10 weeks, which was the goal of the IT team. It was helped by the fact that prior to Windows 10's release, a large number of employees were already using Insider preview builds:
"Prior to product release, there were 38,000 users, roughly 40 percent of employees, internally running Windows 10. Microsoft IT used flighting (delivering pre-release builds of Windows 10 through Windows Update) to make sure that early adopters were running the latest builds as they became available."