Microsoft Visual SourceSafe (VSS) is a discontinued source control program oriented towards small software development projects.

While most commonly used for source code, SourceSafe can handle any type of file in its database, but older versions were shown[1][2] to be unstable when used to store large amounts of non-textual data, such as images and compiled executables.

For multi-user environments, however, it lacks many important features found in other SCM products, including support for atomic commits of multiple files (CVS has the same problem as it is built upon the original RCS).

This, together with historic bugs in the codebase, occasionally led to SourceSafe database corruption, a problem noted by Microsoft.

In this mode, clients do not need write access to a SMB share where they can potentially damage the SS database.

According to Matthew Doar:[18] Microsoft itself used an internally developed version of RCS named SLM until 1999, when it began using a version of Perforce named SourceDepot.The Microsoft Developer Division was using Team Foundation Server for most of its internal projects,[19] although a VSS transcript[citation needed] implied that other large teams use "a mix of customized in-house tools."

This product addresses many of the shortcomings of Visual SourceSafe, making it suitable for larger teams requiring high levels of stability and control over activities.