diff --git a/jps/jps-builders/resources/messages/JpsBuildBundle.properties b/jps/jps-builders/resources/messages/JpsBuildBundle.properties
index 3e7b96c420bb..ced98ae39ef5 100644
--- a/jps/jps-builders/resources/messages/JpsBuildBundle.properties
+++ b/jps/jps-builders/resources/messages/JpsBuildBundle.properties
@@ -26,6 +26,7 @@ progress.message.dependency.analysis.found.0.affected.files=Dependency analysis
 progress.message.finished.saving.caches=Finished, saving caches\u2026
 progress.message.running.after.tasks=Running 'after' tasks
 progress.message.running.before.tasks=Running 'before' tasks
+build.message.conflicting.outputs.error=Output file "{0}" has already been registered by "{1}"
 
 #java
 build.message.0.was.used.to.compile.1={0} was used to compile [{1}]
diff --git a/jps/jps-builders/src/org/jetbrains/jps/incremental/ChunkBuildOutputConsumerImpl.java b/jps/jps-builders/src/org/jetbrains/jps/incremental/ChunkBuildOutputConsumerImpl.java
index 506c2a177b57..1c8915c10bbb 100644
--- a/jps/jps-builders/src/org/jetbrains/jps/incremental/ChunkBuildOutputConsumerImpl.java
+++ b/jps/jps-builders/src/org/jetbrains/jps/incremental/ChunkBuildOutputConsumerImpl.java
@@ -1,28 +1,38 @@
 // Copyright 2000-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.jps.incremental;
 
+import com.intellij.openapi.util.io.FileUtil;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMaps;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jps.builders.BuildTarget;
+import org.jetbrains.jps.builders.JpsBuildBundle;
 import org.jetbrains.jps.builders.impl.BuildOutputConsumerImpl;
+import org.jetbrains.jps.incremental.messages.BuildMessage;
+import org.jetbrains.jps.incremental.messages.CompilerMessage;
 
 import java.io.File;
 import java.io.IOException;
 import java.util.*;
 
-/**
-* @author Eugene Zhuravlev
-*/
 final class ChunkBuildOutputConsumerImpl implements ModuleLevelBuilder.OutputConsumer {
   private final CompileContext myContext;
   private final Map<BuildTarget<?>, BuildOutputConsumerImpl> myTarget2Consumer = new HashMap<>();
   private final Map<String, CompiledClass> myClasses = new HashMap<>();
   private final Map<BuildTarget<?>, Collection<CompiledClass>> myTargetToClassesMap = new HashMap<>();
-
+  private final Int2ObjectMap<String> myOutputToBuilderNameMap = Int2ObjectMaps.synchronize(new Int2ObjectOpenHashMap<>());
+  private volatile String myCurrentBuilderName;
+  
   ChunkBuildOutputConsumerImpl(CompileContext context) {
     myContext = context;
   }
 
+  public void setCurrentBuilderName(String builderName) {
+    myCurrentBuilderName = builderName;
+  }
+
   @Override
   public Collection<CompiledClass> getTargetCompiledClasses(@NotNull BuildTarget<?> target) {
     final Collection<CompiledClass> classes = myTargetToClassesMap.get(target);
@@ -65,6 +75,16 @@ final class ChunkBuildOutputConsumerImpl implements ModuleLevelBuilder.OutputCon
 
   @Override
   public void registerOutputFile(@NotNull BuildTarget<?> target, File outputFile, Collection<String> sourcePaths) throws IOException {
+    final String currentBuilder = myCurrentBuilderName;
+    if (currentBuilder != null) {
+      final String previousBuilder = myOutputToBuilderNameMap.put(FileUtil.fileHashCode(outputFile), currentBuilder);
+      if (previousBuilder != null && !previousBuilder.equals(currentBuilder)) {
+        final String source = sourcePaths.isEmpty()? null : sourcePaths.iterator().next();
+        myContext.processMessage(new CompilerMessage(
+          currentBuilder, BuildMessage.Kind.ERROR, JpsBuildBundle.message("build.message.conflicting.outputs.error", outputFile.getAbsolutePath(), previousBuilder), source
+        ));
+      }
+    }
     BuildOutputConsumerImpl consumer = myTarget2Consumer.get(target);
     if (consumer == null) {
       consumer = new BuildOutputConsumerImpl(target, myContext);
@@ -91,5 +111,6 @@ final class ChunkBuildOutputConsumerImpl implements ModuleLevelBuilder.OutputCon
     myTarget2Consumer.clear();
     myClasses.clear();
     myTargetToClassesMap.clear();
+    myOutputToBuilderNameMap.clear();
   }
 }
diff --git a/jps/jps-builders/src/org/jetbrains/jps/incremental/IncProjectBuilder.java b/jps/jps-builders/src/org/jetbrains/jps/incremental/IncProjectBuilder.java
index 3901ffed3442..92b1fa6f0c69 100644
--- a/jps/jps-builders/src/org/jetbrains/jps/incremental/IncProjectBuilder.java
+++ b/jps/jps-builders/src/org/jetbrains/jps/incremental/IncProjectBuilder.java
@@ -1509,6 +1509,7 @@ public final class IncProjectBuilder {
 
             try {
               for (ModuleLevelBuilder builder : builders) {
+                outputConsumer.setCurrentBuilderName(builder.getPresentableName());
                 processDeletedPaths(context, chunk.getTargets());
                 long start = System.nanoTime();
                 int processedSourcesBefore = outputConsumer.getNumberOfProcessedSources();
@@ -1556,6 +1557,7 @@ public final class IncProjectBuilder {
               }
             }
             finally {
+              outputConsumer.setCurrentBuilderName(null);
               final boolean moreToCompile = JavaBuilderUtil.updateMappingsOnRoundCompletion(context, dirtyFilesHolder, chunk);
               if (moreToCompile) {
                 nextPassRequired = true;