diff --git a/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/diagnostics.expected b/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/diagnostics.expected
new file mode 100644
index 00000000000..1c22e0f376e
--- /dev/null
+++ b/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/diagnostics.expected
@@ -0,0 +1,32 @@
+{
+  "attributes": {},
+  "helpLinks": [],
+  "internal": false,
+  "location": {},
+  "markdownMessage": "CodeQL was unable to build the following projects using MSBuild:\n- `test.sln`\nSet up a [manual build command](https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/configuring-the-codeql-workflow-for-compiled-languages).",
+  "severity": "error",
+  "source": {
+    "extractorName": "csharp",
+    "id": "csharp/autobuilder/msbuild-build-failure",
+    "name": "Some projects or solutions failed to build using MSBuild"
+  },
+  "visibility": {
+    "statusPage": true
+  }
+}
+{
+  "attributes": {},
+  "helpLinks": [],
+  "internal": false,
+  "location": {},
+  "markdownMessage": "Some project files were not found when CodeQL built your project:\n\n- `Example.csproj`\n- `Example.Test.csproj`\n\nThis may lead to subsequent failures. You can check for common causes for missing project files:\n\n- Ensure that the project is built using the [intended operating system](https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idruns-on) and that filenames on case-sensitive platforms are correctly specified.\n- If your repository uses Git submodules, ensure that those are [checked out](https://github.com/actions/checkout#usage) before the CodeQL action is run.\n- If you auto-generate some project files as part of your build process, ensure that these are generated before the CodeQL action is run.",
+  "severity": "error",
+  "source": {
+    "extractorName": "csharp",
+    "id": "csharp/autobuilder/missing-project-files",
+    "name": "Missing project files"
+  },
+  "visibility": {
+    "statusPage": true
+  }
+}
diff --git a/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/test.py b/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/test.py
new file mode 100644
index 00000000000..62c4d3934a4
--- /dev/null
+++ b/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/test.py
@@ -0,0 +1,5 @@
+from create_database_utils import *
+from diagnostics_test_utils import *
+
+run_codeql_database_create([], db=None, lang="csharp", runFunction=runUnsuccessfully)
+check_diagnostics()
diff --git a/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/test.sln b/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/test.sln
new file mode 100644
index 00000000000..60a70f32fe2
--- /dev/null
+++ b/csharp/ql/integration-tests/all-platforms/diag_missing_project_files/test.sln
@@ -0,0 +1,26 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 2012
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Example", "Example.csproj", "{F70CE6B6-1735-4AD2-B1EB-B91FCD1012D1}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Example.Test", "Example.Test.csproj", "{F4587B5F-9918-4079-9291-5A08CD9761FB}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|x86 = Debug|x86
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{F70CE6B6-1735-4AD2-B1EB-B91FCD1012D1}.Debug|x86.ActiveCfg = Debug|x86
+		{F70CE6B6-1735-4AD2-B1EB-B91FCD1012D1}.Debug|x86.Build.0 = Debug|x86
+		{F70CE6B6-1735-4AD2-B1EB-B91FCD1012D1}.Release|x86.ActiveCfg = Release|x86
+		{F70CE6B6-1735-4AD2-B1EB-B91FCD1012D1}.Release|x86.Build.0 = Release|x86
+		{F4587B5F-9918-4079-9291-5A08CD9761FB}.Debug|x86.ActiveCfg = Debug|x86
+		{F4587B5F-9918-4079-9291-5A08CD9761FB}.Debug|x86.Build.0 = Debug|x86
+		{F4587B5F-9918-4079-9291-5A08CD9761FB}.Release|x86.ActiveCfg = Release|x86
+		{F4587B5F-9918-4079-9291-5A08CD9761FB}.Release|x86.Build.0 = Release|x86
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal