quality:corruption
Version control system

Up to and including every version before Windows 2000, Microsoft used an in-house version control system named Source Library Manager (SLM). Shortly after Windows 2000 was released, Microsoft switched to a fork of Perforce named Source Depot. This system was used up until 2017 once the system could not keep up with the size of Windows. Microsoft had begun to integrate Git into Team Foundation Server in 2013, but Windows (and Office) continued to rely on Source Depot. The Windows code was divided among 65 different repositories with a kind of virtualization layer to produce unified view of all of the code.

In 2017 Microsoft announced that it would start using Git, an open source version control system created by Linus Torvalds and in May 2017 they reported that the migration into a new Git repository was complete.