diff --git a/news/2 Fixes/17111.md b/news/2 Fixes/17111.md
new file mode 100644
index 000000000000..2e735435b2dc
--- /dev/null
+++ b/news/2 Fixes/17111.md	
@@ -0,0 +1 @@
+Ensure line feeds are changed to CRLF in test messages.
diff --git a/src/client/testing/testController/common/resultsHelper.ts b/src/client/testing/testController/common/resultsHelper.ts
index 7eaceeb398d0..823a87c79df2 100644
--- a/src/client/testing/testController/common/resultsHelper.ts
+++ b/src/client/testing/testController/common/resultsHelper.ts
@@ -5,6 +5,7 @@ import * as fsapi from 'fs-extra';
 import { Location, TestItem, TestMessage, TestRun } from 'vscode';
 import { getRunIdFromRawData, getTestCaseNodes } from './testItemUtilities';
 import { TestData } from './types';
+import { fixLogLines } from './utils';
 
 type TestSuiteResult = {
     $: {
@@ -113,7 +114,7 @@ export async function updateResultFromJunitXml(
                     }
 
                     runInstance.errored(node, message);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                 } else if (result.failure) {
                     failures += 1;
                     const failure = result.failure[0];
@@ -125,23 +126,23 @@ export async function updateResultFromJunitXml(
                     }
 
                     runInstance.failed(node, message);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                 } else if (result.skipped) {
                     skipped += 1;
                     const skip = result.skipped[0];
                     const text = `${rawTestCaseNode.rawId} Skipped: [${skip.$.type}]${skip.$.message}\r\n`;
 
                     runInstance.skipped(node);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                 } else {
                     passed += 1;
                     const text = `${rawTestCaseNode.rawId} Passed\r\n`;
                     runInstance.passed(node);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                 }
             } else {
                 const text = `Test result not found for: ${rawTestCaseNode.rawId}\r\n`;
-                runInstance.appendOutput(text);
+                runInstance.appendOutput(fixLogLines(text));
                 const message = new TestMessage(text);
 
                 if (node.uri && node.range) {
diff --git a/src/client/testing/testController/common/utils.ts b/src/client/testing/testController/common/utils.ts
new file mode 100644
index 000000000000..13fc76a37199
--- /dev/null
+++ b/src/client/testing/testController/common/utils.ts
@@ -0,0 +1,7 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+export function fixLogLines(content: string): string {
+    const lines = content.split(/\r?\n/g);
+    return `${lines.join('\r\n')}\r\n`;
+}
diff --git a/src/client/testing/testController/unittest/runner.ts b/src/client/testing/testController/unittest/runner.ts
index 9e053893740a..71f6dd3f57b7 100644
--- a/src/client/testing/testController/unittest/runner.ts
+++ b/src/client/testing/testController/unittest/runner.ts
@@ -12,6 +12,7 @@ import { ITestRunner, ITestDebugLauncher, IUnitTestSocketServer, LaunchOptions,
 import { TEST_OUTPUT_CHANNEL } from '../../constants';
 import { getTestCaseNodes } from '../common/testItemUtilities';
 import { ITestRun, ITestsRunner, TestData, TestRunInstanceOptions, TestRunOptions } from '../common/types';
+import { fixLogLines } from '../common/utils';
 import { getTestRunArgs } from './arguments';
 
 interface ITestData {
@@ -102,7 +103,7 @@ export class UnittestRunner implements ITestsRunner {
                 if (data.outcome === 'passed' || data.outcome === 'failed-expected') {
                     const text = `${rawTestCase.rawId} Passed\r\n`;
                     runInstance.passed(testCase);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                     counts.passed += 1;
                 } else if (data.outcome === 'failed' || data.outcome === 'passed-unexpected') {
                     const traceback = data.traceback
@@ -116,7 +117,7 @@ export class UnittestRunner implements ITestsRunner {
                     }
 
                     runInstance.failed(testCase, message);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                     counts.failed += 1;
                     if (failFast) {
                         stopTesting = true;
@@ -133,7 +134,7 @@ export class UnittestRunner implements ITestsRunner {
                     }
 
                     runInstance.errored(testCase, message);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                     counts.errored += 1;
                     if (failFast) {
                         stopTesting = true;
@@ -144,11 +145,11 @@ export class UnittestRunner implements ITestsRunner {
                         : '';
                     const text = `${rawTestCase.rawId} Skipped: ${data.message}\r\n${traceback}\r\n`;
                     runInstance.skipped(testCase);
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                     counts.skipped += 1;
                 } else {
                     const text = `Unknown outcome type for test ${rawTestCase.rawId}: ${data.outcome}`;
-                    runInstance.appendOutput(text);
+                    runInstance.appendOutput(fixLogLines(text));
                     const message = new TestMessage(text);
                     if (testCase.uri && testCase.range) {
                         message.location = new Location(testCase.uri, testCase.range);