diff --git a/jps/model-impl/src/org/jetbrains/jps/service/impl/JpsServiceManagerImpl.java b/jps/model-impl/src/org/jetbrains/jps/service/impl/JpsServiceManagerImpl.java
index d85561d6937b..2f566f681578 100644
--- a/jps/model-impl/src/org/jetbrains/jps/service/impl/JpsServiceManagerImpl.java
+++ b/jps/model-impl/src/org/jetbrains/jps/service/impl/JpsServiceManagerImpl.java
@@ -1,22 +1,9 @@
-/*
- * Copyright 2000-2014 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2020 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.service.impl;
 
 import com.intellij.openapi.progress.ProcessCanceledException;
 import com.intellij.util.containers.ContainerUtil;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jps.plugin.JpsPluginManager;
 import org.jetbrains.jps.service.JpsServiceManager;
@@ -82,16 +69,19 @@ public class JpsServiceManagerImpl extends JpsServiceManager {
     return (List<T>)cached;
   }
 
-  private boolean cleanupExtensionCache() {
-    JpsPluginManager manager = myPluginManager;
-    if (manager != null) {
-      int stamp = manager.getModificationStamp();
-      if (myModificationStamp.getAndSet(stamp) != stamp) {
-        myExtensions.clear();
-        return true;
+  @ApiStatus.Internal
+  public boolean cleanupExtensionCache() {
+    synchronized (myExtensions) {
+      JpsPluginManager manager = myPluginManager;
+      if (manager != null) {
+        int stamp = manager.getModificationStamp();
+        if (myModificationStamp.getAndSet(stamp) != stamp) {
+          myExtensions.clear();
+          return true;
+        }
       }
+      return false;
     }
-    return false;
   }
 
   @NotNull
diff --git a/platform/platform-impl/src/com/intellij/jps/impl/JpsIdePluginManagerImpl.java b/platform/platform-impl/src/com/intellij/jps/impl/JpsIdePluginManagerImpl.java
index 5eb499664c33..20e2423a6017 100644
--- a/platform/platform-impl/src/com/intellij/jps/impl/JpsIdePluginManagerImpl.java
+++ b/platform/platform-impl/src/com/intellij/jps/impl/JpsIdePluginManagerImpl.java
@@ -1,9 +1,12 @@
-// Copyright 2000-2019 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.
+// Copyright 2000-2020 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 com.intellij.jps.impl;
 
 import com.intellij.openapi.application.Application;
 import com.intellij.openapi.application.ApplicationManager;
-import com.intellij.openapi.extensions.*;
+import com.intellij.openapi.extensions.ExtensionPoint;
+import com.intellij.openapi.extensions.ExtensionPointListener;
+import com.intellij.openapi.extensions.ExtensionsArea;
+import com.intellij.openapi.extensions.PluginDescriptor;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.module.ModuleManager;
 import com.intellij.openapi.project.Project;
@@ -27,6 +30,8 @@ import org.jetbrains.jps.model.serialization.module.JpsModuleRootModelSerializer
 import org.jetbrains.jps.model.serialization.module.JpsModuleSourceRootPropertiesSerializer;
 import org.jetbrains.jps.model.serialization.module.UnknownSourceRootPropertiesSerializer;
 import org.jetbrains.jps.plugin.JpsPluginManager;
+import org.jetbrains.jps.service.JpsServiceManager;
+import org.jetbrains.jps.service.impl.JpsServiceManagerImpl;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -126,6 +131,10 @@ public final class JpsIdePluginManagerImpl extends JpsPluginManager {
     }
     myExternalBuildPlugins.remove(pluginDescriptor);
     myModificationStamp.incrementAndGet();
+    JpsServiceManager jpsServiceManager = JpsServiceManager.getInstance();
+    if (jpsServiceManager instanceof JpsServiceManagerImpl) {
+      ((JpsServiceManagerImpl)jpsServiceManager).cleanupExtensionCache();
+    }
   }
 
   private void handlePluginAdded(@NotNull PluginDescriptor pluginDescriptor) {