diff --git a/platform/core-api/src/com/intellij/lang/folding/CompositeFoldingBuilder.java b/platform/core-api/src/com/intellij/lang/folding/CompositeFoldingBuilder.java
index d80e6639a1dd..4fdc9bf64a06 100644
--- a/platform/core-api/src/com/intellij/lang/folding/CompositeFoldingBuilder.java
+++ b/platform/core-api/src/com/intellij/lang/folding/CompositeFoldingBuilder.java
@@ -18,12 +18,14 @@ package com.intellij.lang.folding;
 
 import com.intellij.lang.ASTNode;
 import com.intellij.openapi.editor.Document;
-import com.intellij.openapi.project.DumbAware;
+import com.intellij.openapi.project.DumbService;
+import com.intellij.openapi.project.PossiblyDumbAware;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.PsiElement;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -38,7 +40,7 @@ import java.util.Set;
  * @see LanguageFolding
  * @since 9.0
  */
-public class CompositeFoldingBuilder extends FoldingBuilderEx implements DumbAware {
+public class CompositeFoldingBuilder extends FoldingBuilderEx implements PossiblyDumbAware {
   public static final Key<FoldingBuilder> FOLDING_BUILDER = new Key<FoldingBuilder>("FOLDING_BUILDER");
   private final List<FoldingBuilder> myBuilders;
 
@@ -56,7 +58,7 @@ public class CompositeFoldingBuilder extends FoldingBuilderEx implements DumbAwa
     final List<FoldingDescriptor> descriptors = new ArrayList<FoldingDescriptor>();
     final Set<TextRange> rangesCoveredByDescriptors = ContainerUtil.newHashSet();
 
-    for (FoldingBuilder builder : myBuilders) {
+    for (FoldingBuilder builder : DumbService.getInstance(root.getProject()).filterByDumbAwareness(myBuilders)) {
       for (FoldingDescriptor descriptor : LanguageFolding.buildFoldingDescriptors(builder, root, document, quick)) {
         if (rangesCoveredByDescriptors.add(descriptor.getRange())) {
           descriptor.getElement().putUserData(FOLDING_BUILDER, builder);
@@ -71,24 +73,38 @@ public class CompositeFoldingBuilder extends FoldingBuilderEx implements DumbAwa
   @Override
   public String getPlaceholderText(@NotNull ASTNode node, @NotNull TextRange range) {
     final FoldingBuilder builder = node.getUserData(FOLDING_BUILDER);
-    return builder == null ? node.getText() : builder instanceof FoldingBuilderEx
-                                              ? ((FoldingBuilderEx)builder).getPlaceholderText(node, range)
-                                              : builder.getPlaceholderText(node);
+    return !mayUseBuilder(node, builder) ? node.getText() :
+           builder instanceof FoldingBuilderEx ? ((FoldingBuilderEx)builder).getPlaceholderText(node, range)
+                                               : builder.getPlaceholderText(node);
   }
 
   @Override
   public String getPlaceholderText(@NotNull ASTNode node) {
     final FoldingBuilder builder = node.getUserData(FOLDING_BUILDER);
-    return builder == null ? node.getText() : builder.getPlaceholderText(node);
+    return !mayUseBuilder(node, builder) ? node.getText() : builder.getPlaceholderText(node);
   }
 
   public boolean isCollapsedByDefault(@NotNull ASTNode node) {
     final FoldingBuilder builder = node.getUserData(FOLDING_BUILDER);
-    return builder != null && builder.isCollapsedByDefault(node);
+    return mayUseBuilder(node, builder) && builder.isCollapsedByDefault(node);
+  }
+
+  private static boolean mayUseBuilder(@NotNull ASTNode node, @Nullable FoldingBuilder builder) {
+    return builder != null && (DumbService.isDumbAware(builder) || !DumbService.isDumb(node.getPsi().getProject()));
   }
 
   @Override
   public String toString() {
     return getClass().getSimpleName() + myBuilders;
   }
+
+  @Override
+  public boolean isDumbAware() {
+    for (FoldingBuilder builder : myBuilders) {
+      if (DumbService.isDumbAware(builder)) {
+        return true;
+      }
+    }
+    return false;
+  }
 }
diff --git a/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingPolicy.java b/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingPolicy.java
index 945b754a004a..577a58d04d62 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingPolicy.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/folding/impl/FoldingPolicy.java
@@ -19,13 +19,16 @@ package com.intellij.codeInsight.folding.impl;
 import com.intellij.lang.Language;
 import com.intellij.lang.folding.FoldingBuilder;
 import com.intellij.lang.folding.LanguageFolding;
+import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.extensions.Extensions;
+import com.intellij.openapi.project.IndexNotReadyException;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 public class FoldingPolicy {
+  private static final Logger LOG = Logger.getInstance("#com.intellij.codeInsight.folding.impl.FoldingPolicy");
   
   private static final GenericElementSignatureProvider GENERIC_PROVIDER = new GenericElementSignatureProvider();
   
@@ -34,7 +37,13 @@ public class FoldingPolicy {
   public static boolean isCollapseByDefault(PsiElement element) {
     final Language lang = element.getLanguage();
     final FoldingBuilder foldingBuilder = LanguageFolding.INSTANCE.forLanguage(lang);
-    return foldingBuilder != null && foldingBuilder.isCollapsedByDefault(element.getNode());
+    try {
+      return foldingBuilder != null && foldingBuilder.isCollapsedByDefault(element.getNode());
+    }
+    catch (IndexNotReadyException e) {
+      LOG.error(e);
+      return false;
+    }
   }
 
   @Nullable