Do we need proportional number of Visual SourceSafe licenses from Microsoft to use SourceAnywhere for VSS?

Yes. To use SourceAnywhere for VSS, you must be a licensed user of Microsoft Visual SourceSafe. Please refer to the Microsoft Visual SourceSafe license agreement for specific details.

However, if you already have a VSS license, you do not need an additional VSS license to use SourceAnywhere for VSS.