We have the convention of versioning our builds as [major].[minor].[micro].[revision], e.g. 2.1.2.33546.
Our build-script automatically updates an AssemblyInfo.cs file c
One option might be to just use the [AssemblyFileVersion]; this still raises a warning, but it'll build, at least:
[AssemblyFileVersion]
[assembly: AssemblyFileVersion("1.0.0.80000")]