diff --git a/src/Microsoft.TestPlatform.CrossPlatEngine/DataCollection/InProcDataCollectionExtensionManager.cs b/src/Microsoft.TestPlatform.CrossPlatEngine/DataCollection/InProcDataCollectionExtensionManager.cs
index 413db1d17a..461274011f 100644
--- a/src/Microsoft.TestPlatform.CrossPlatEngine/DataCollection/InProcDataCollectionExtensionManager.cs
+++ b/src/Microsoft.TestPlatform.CrossPlatEngine/DataCollection/InProcDataCollectionExtensionManager.cs
@@ -29,7 +29,7 @@ internal class InProcDataCollectionExtensionManager
 
     private readonly IDataCollectionSink _inProcDataCollectionSink;
     private readonly string? _defaultCodeBase;
-    private readonly List<string?> _codeBasePaths;
+    internal /* for testing purposes */ readonly HashSet<string?> CodeBasePaths;
     private readonly IFileHelper _fileHelper;
 
     internal IDictionary<string, IInProcDataCollector> InProcDataCollectors;
@@ -61,13 +61,13 @@ protected InProcDataCollectionExtensionManager(string? runSettings, ITestEventsP
         _inProcDataCollectionSink = new InProcDataCollectionSink();
         _defaultCodeBase = defaultCodeBase;
         _fileHelper = fileHelper;
-        _codeBasePaths = new List<string?> { _defaultCodeBase };
+        CodeBasePaths = new HashSet<string?>(StringComparer.OrdinalIgnoreCase) { _defaultCodeBase };
 
         // Get Datacollector code base paths from test plugin cache
         var extensionPaths = testPluginCache.GetExtensionPaths(DataCollectorEndsWithPattern);
         foreach (var extensionPath in extensionPaths)
         {
-            _codeBasePaths.Add(Path.GetDirectoryName(extensionPath)!);
+            CodeBasePaths.Add(Path.GetDirectoryName(extensionPath)!);
         }
 
         // Initialize InProcDataCollectors
@@ -248,7 +248,7 @@ private string GetCodebase(string codeBase)
             return codeBase;
         }
 
-        foreach (var extensionPath in _codeBasePaths)
+        foreach (var extensionPath in CodeBasePaths)
         {
             if (extensionPath is null)
             {
diff --git a/test/Microsoft.TestPlatform.CrossPlatEngine.UnitTests/DataCollection/InProcDataCollectionExtensionManagerTests.cs b/test/Microsoft.TestPlatform.CrossPlatEngine.UnitTests/DataCollection/InProcDataCollectionExtensionManagerTests.cs
index 769617af26..730d1a0a07 100644
--- a/test/Microsoft.TestPlatform.CrossPlatEngine.UnitTests/DataCollection/InProcDataCollectionExtensionManagerTests.cs
+++ b/test/Microsoft.TestPlatform.CrossPlatEngine.UnitTests/DataCollection/InProcDataCollectionExtensionManagerTests.cs
@@ -8,6 +8,7 @@
 using System.Reflection;
 using System.Xml;
 
+using Microsoft.TestPlatform.TestUtilities;
 using Microsoft.VisualStudio.TestPlatform.Common.ExtensionFramework;
 using Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.DataCollection;
 using Microsoft.VisualStudio.TestPlatform.CrossPlatEngine.DataCollection.Interfaces;
@@ -53,6 +54,26 @@ public InProcDataCollectionExtensionManagerTests()
         _inProcDataCollectionManager = new TestableInProcDataCollectionExtensionManager(_settingsXml, _mockTestEventsPublisher.Object, _defaultCodebase, _testPluginCache, _mockFileHelper.Object);
     }
 
+    [TestMethod]
+    public void CodeBasePathsAreDeduplicatedWithCaseIgnoring()
+    {
+        var testPluginCache = new TestableTestPluginCache();
+        // the boolean argument refers to adding the paths to which list(we have two lists)and the duplicate happened when we merged the two lists and they had the same path
+        testPluginCache.UpdateExtensions(new List<string> { Path.Combine(Temp, "DEDUPLICATINGWITHCASEIGNORING1", "Collector.dll") }, false);
+        var directory1 = Path.Combine(Temp, "DeduplicatingWithCaseIgnoring1");
+        var directory2 = Path.Combine(Temp, "DeduplicatingWithCaseIgnoring2");
+        testPluginCache.UpdateExtensions(new List<string> { Path.Combine(directory1, "Collector.dll"), Path.Combine(directory2, "Collector.dll") }, true);
+
+        var inProcDataCollectionExtensionManager = new TestableInProcDataCollectionExtensionManager(_settingsXml, _mockTestEventsPublisher.Object, null, testPluginCache, _mockFileHelper.Object);
+
+        Assert.AreEqual(3, inProcDataCollectionExtensionManager.CodeBasePaths.Count); // "CodeBasePaths" contains the two extensions(after removing duplicates) and the "_defaultCodebase"
+
+        Assert.IsTrue(inProcDataCollectionExtensionManager.CodeBasePaths.Contains(null));
+        Assert.IsTrue(inProcDataCollectionExtensionManager.CodeBasePaths.Contains(directory1));
+        Assert.IsTrue(inProcDataCollectionExtensionManager.CodeBasePaths.Contains(directory2));
+    }
+
+
     [TestMethod]
     public void InProcDataCollectionExtensionManagerShouldLoadsDataCollectorsFromRunSettings()
     {
@@ -275,7 +296,7 @@ public void TriggerTestCaseEndShouldtBeCalledMultipleTimesInDataDrivenScenario()
 
     internal class TestableInProcDataCollectionExtensionManager : InProcDataCollectionExtensionManager
     {
-        public TestableInProcDataCollectionExtensionManager(string runSettings, ITestEventsPublisher mockTestEventsPublisher, string defaultCodebase, TestPluginCache testPluginCache, IFileHelper fileHelper)
+        public TestableInProcDataCollectionExtensionManager(string runSettings, ITestEventsPublisher mockTestEventsPublisher, string? defaultCodebase, TestPluginCache testPluginCache, IFileHelper fileHelper)
             : base(runSettings, mockTestEventsPublisher, defaultCodebase, testPluginCache, fileHelper)
         {
         }