diff --git a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
index 5538724795f6..bf687a8ff3e9 100644
--- a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
+++ b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
@@ -2470,6 +2470,7 @@ public class FileBasedIndexImpl extends FileBasedIndex {
 
   @Override
   public void removeIndexableSet(@NotNull IndexableFileSet set) {
+    if (!myIndexableSetToProjectMap.containsKey(set)) return; // avoid second unfiltered forceUpdate
     myChangedFilesCollector.forceUpdate(myIndexableSetToProjectMap.get(set), null, null, true);
     IndexingStamp.flushCaches();
     myIndexableSets.remove(set);