diff --git a/ln.build/support/dotnet/CSProjHelper.cs b/ln.build/support/dotnet/CSProjHelper.cs
index 60a5731..a96d667 100644
--- a/ln.build/support/dotnet/CSProjHelper.cs
+++ b/ln.build/support/dotnet/CSProjHelper.cs
@@ -30,7 +30,7 @@ namespace ln.build.support.dotnet
             XmlDocument projectFile = new XmlDocument();
             projectFile.Load(FileName);
             XmlNode nodeVersion = projectFile.SelectSingleNode("Project/PropertyGroup/Version");
-            return SemVersion.Parse(nodeVersion.InnerText);
+            return (nodeVersion == null) ? null : SemVersion.Parse(nodeVersion.InnerText);
         }
 
         public void SetVersion(SemVersion version)