diff --git a/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/coreEnvironmentUtils.kt b/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/coreEnvironmentUtils.kt
index fb121b95eda..78426681cdd 100644
--- a/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/coreEnvironmentUtils.kt
+++ b/compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/coreEnvironmentUtils.kt
@@ -44,7 +44,8 @@ inline fun List<KotlinSourceRoot>.forAllFiles(
     val virtualFileCreator = PreprocessedFileCreator(project)
 
     for ((sourceRootPath, isCommon) in this) {
-        val vFile = localFileSystem.findFileByPath(sourceRootPath)
+        val sourceRoot = File(sourceRootPath)
+        val vFile = localFileSystem.findFileByPath(sourceRoot.normalize().path)
         if (vFile == null) {
             val message = "Source file or directory not found: $sourceRootPath"
 
@@ -63,10 +64,10 @@ inline fun List<KotlinSourceRoot>.forAllFiles(
             continue
         }
 
-        for (file in File(sourceRootPath).walkTopDown()) {
+        for (file in sourceRoot.walkTopDown()) {
             if (!file.isFile) continue
 
-            val virtualFile = localFileSystem.findFileByPath(file.absolutePath)?.let(virtualFileCreator::create)
+            val virtualFile = localFileSystem.findFileByPath(file.absoluteFile.normalize().path)?.let(virtualFileCreator::create)
             if (virtualFile != null && processedFiles.add(virtualFile)) {
                 body(virtualFile, isCommon)
             }
diff --git a/compiler/testData/cli/jvm/duplicateSourcesNormalized.args b/compiler/testData/cli/jvm/duplicateSourcesNormalized.args
new file mode 100644
index 00000000000..9600e48fbf8
--- /dev/null
+++ b/compiler/testData/cli/jvm/duplicateSourcesNormalized.args
@@ -0,0 +1,4 @@
+$TESTDATA_DIR$/simple.kt
+$TESTDATA_DIR$/./simple.kt
+-d
+$TEMP_DIR$
diff --git a/compiler/testData/cli/jvm/duplicateSourcesNormalized.out b/compiler/testData/cli/jvm/duplicateSourcesNormalized.out
new file mode 100644
index 00000000000..d86bac9de59
--- /dev/null
+++ b/compiler/testData/cli/jvm/duplicateSourcesNormalized.out
@@ -0,0 +1 @@
+OK
diff --git a/compiler/tests-gen/org/jetbrains/kotlin/cli/CliTestGenerated.java b/compiler/tests-gen/org/jetbrains/kotlin/cli/CliTestGenerated.java
index 5cb83aa19f7..00a96c39773 100644
--- a/compiler/tests-gen/org/jetbrains/kotlin/cli/CliTestGenerated.java
+++ b/compiler/tests-gen/org/jetbrains/kotlin/cli/CliTestGenerated.java
@@ -264,6 +264,11 @@ public class CliTestGenerated extends AbstractCliTest {
             runTest("compiler/testData/cli/jvm/duplicateSourcesInModule.args");
         }
 
+        @TestMetadata("duplicateSourcesNormalized.args")
+        public void testDuplicateSourcesNormalized() throws Exception {
+            runTest("compiler/testData/cli/jvm/duplicateSourcesNormalized.args");
+        }
+
         @TestMetadata("emptySources.args")
         public void testEmptySources() throws Exception {
             runTest("compiler/testData/cli/jvm/emptySources.args");