diff --git a/src/Cli/dotnet/commands/dotnet-sln/add/Program.cs b/src/Cli/dotnet/commands/dotnet-sln/add/Program.cs
index de524b2893e0..e7c7d39e1291 100644
--- a/src/Cli/dotnet/commands/dotnet-sln/add/Program.cs
+++ b/src/Cli/dotnet/commands/dotnet-sln/add/Program.cs
@@ -116,7 +116,7 @@ private async Task AddProjectsToSolutionAsync(string solutionFileFullPath, IEnum
 
                 try
                 {
-                    AddProject(solution, relativePath, projectPath, solutionFolder);
+                    AddProject(solution, relativePath, projectPath, solutionFolder, serializer);
                 }
                 catch (InvalidProjectFileException ex)
                 {
@@ -130,7 +130,7 @@ private async Task AddProjectsToSolutionAsync(string solutionFileFullPath, IEnum
             await serializer.SaveAsync(solutionFileFullPath, solution, cancellationToken);
         }
 
-        private void AddProject(SolutionModel solution, string solutionRelativeProjectPath, string fullPath, SolutionFolderModel? solutionFolder)
+        private void AddProject(SolutionModel solution, string solutionRelativeProjectPath, string fullPath, SolutionFolderModel? solutionFolder, ISolutionSerializer serializer = null)
         {
             // Open project instance to see if it is a valid project
             ProjectRootElement projectRootElement = ProjectRootElement.Open(fullPath);
@@ -153,7 +153,7 @@ private void AddProject(SolutionModel solution, string solutionRelativeProjectPa
             // Add settings based on existing project instance
             ProjectInstance projectInstance = new ProjectInstance(projectRootElement);
             string projectInstanceId = projectInstance.GetProjectId();
-            if (!string.IsNullOrEmpty(projectInstanceId))
+            if (!string.IsNullOrEmpty(projectInstanceId) && serializer is ISolutionSerializer<SlnV12SerializerSettings>)
             {
                 project.Id = new Guid(projectInstanceId);
             }
diff --git a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProj.slnx b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProj.slnx
index 7fcda19ce217..b8e10870f971 100644
--- a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProj.slnx
+++ b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProj.slnx
@@ -8,5 +8,5 @@
     <Platform Solution="*|x64" Project="x64" />
     <Platform Solution="*|x86" Project="x86" />
   </Project>
-  <Project Path="Lib/Lib.csproj" Id="__LIB_PROJECT_GUID__"/>
+  <Project Path="Lib/Lib.csproj" />
 </Solution>
diff --git a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProjToEmptySln.slnx b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProjToEmptySln.slnx
index 0f8bf2b15b63..e3caa7e0055a 100644
--- a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProjToEmptySln.slnx
+++ b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingLibProjToEmptySln.slnx
@@ -4,5 +4,5 @@
     <Platform Name="x64" />
     <Platform Name="x86" />
   </Configurations>
-  <Project Path="Lib/Lib.csproj" Id="__LIB_PROJECT_GUID__" />
+  <Project Path="Lib/Lib.csproj" />
 </Solution>
diff --git a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingNestedProj.slnx b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingNestedProj.slnx
index 96ecc778b697..d79132291fc5 100644
--- a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingNestedProj.slnx
+++ b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingNestedProj.slnx
@@ -5,7 +5,7 @@
     <Platform Name="x86" />
   </Configurations>
   <Folder Name="/src/">
-    <Project Path="src/Lib/Lib.csproj" Id="__LIB_PROJECT_GUID__" />
+    <Project Path="src/Lib/Lib.csproj" />
   </Folder>
   <Project Path="App.csproj">
     <Platform Solution="*|x64" Project="x64" />
diff --git a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithInRootOption.slnx b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithInRootOption.slnx
index 5eb44301b7e2..4b18efe59dab 100644
--- a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithInRootOption.slnx
+++ b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithInRootOption.slnx
@@ -8,5 +8,5 @@
     <Platform Solution="*|x64" Project="x64" />
     <Platform Solution="*|x86" Project="x86" />
   </Project>
-  <Project Path="src/Lib/Lib.csproj" Id="__LIB_PROJECT_GUID__"/>
+  <Project Path="src/Lib/Lib.csproj" />
 </Solution>
diff --git a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithSolutionFolderOption.slnx b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithSolutionFolderOption.slnx
index 238f33b90636..72b17f549402 100644
--- a/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithSolutionFolderOption.slnx
+++ b/test/TestAssets/TestProjects/SolutionFilesTemplates/ExpectedSlnFileAfterAddingProjectWithSolutionFolderOption.slnx
@@ -5,7 +5,7 @@
     <Platform Name="x86" />
   </Configurations>
   <Folder Name="/TestFolder/">
-    <Project Path="src/Lib/Lib.csproj" Id="__LIB_PROJECT_GUID__" />
+    <Project Path="src/Lib/Lib.csproj" />
   </Folder>
   <Project Path="App.csproj">
     <Platform Solution="*|x64" Project="x64" />
diff --git a/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithAdditionalConfigs.slnx b/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithAdditionalConfigs.slnx
index 740e1b4fed5a..339ed04dc998 100644
--- a/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithAdditionalConfigs.slnx
+++ b/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithAdditionalConfigs.slnx
@@ -7,7 +7,7 @@
     <Platform Name="x64" />
     <Platform Name="x86" />
   </Configurations>
-  <Project Path="ProjectWithAdditionalConfigs/ProjectWithAdditionalConfigs.csproj" Id="a302325b-d680-4c0e-8680-7ae283981624">
+  <Project Path="ProjectWithAdditionalConfigs/ProjectWithAdditionalConfigs.csproj">
     <BuildType Solution="Foo Bar|*" Project="FooBar" />
     <Platform Solution="*|x64" Project="x64" />
     <Platform Solution="*|x86" Project="x86" />
diff --git a/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithMatchingConfigs.slnx b/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithMatchingConfigs.slnx
index 13d2aa95a9f9..22585769d919 100644
--- a/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithMatchingConfigs.slnx
+++ b/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithMatchingConfigs.slnx
@@ -7,7 +7,7 @@
     <Platform Name="x64" />
     <Platform Name="x86" />
   </Configurations>
-  <Project Path="ProjectWithMatchingConfigs/ProjectWithMatchingConfigs.csproj"  Id="c9601ca2-db64-4fb6-b463-368c7764bf0d">
+  <Project Path="ProjectWithMatchingConfigs/ProjectWithMatchingConfigs.csproj">
     <BuildType Solution="Foo Bar|*" Project="FooBar" />
     <Platform Solution="*|x64" Project="x64" />
     <Platform Solution="*|x86" Project="x86" />
diff --git a/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithoutMatchingConfigs.slnx b/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithoutMatchingConfigs.slnx
index 48f5fc01aaa2..0a705d1431fb 100644
--- a/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithoutMatchingConfigs.slnx
+++ b/test/TestAssets/TestProjects/TestAppWithSlnAndProjectConfigs/Results/ExpectedSlnFileAfterAddingProjectWithoutMatchingConfigs.slnx
@@ -7,7 +7,7 @@
     <Platform Name="x64" />
     <Platform Name="x86" />
   </Configurations>
-  <Project Path="ProjectWithoutMatchingConfigs/ProjectWithoutMatchingConfigs.csproj"  Id="c49b64de-4401-4825-8a88-10dcb5950e57">
+  <Project Path="ProjectWithoutMatchingConfigs/ProjectWithoutMatchingConfigs.csproj" >
     <BuildType Solution="Foo Bar|*" Project="Debug" />
   </Project>
 </Solution>