diff --git a/platform/lang-impl/src/com/intellij/codeInsight/actions/FormatChangedTextUtil.java b/platform/lang-impl/src/com/intellij/codeInsight/actions/FormatChangedTextUtil.java
index 3b51cc9ad976..dadafc7a7d84 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/actions/FormatChangedTextUtil.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/actions/FormatChangedTextUtil.java
@@ -250,7 +250,7 @@ public class FormatChangedTextUtil {
   }
 
   @NotNull
-  public static List<TextRange> getChangedTextRanges(@NotNull Project project, @NotNull PsiFile file) {
+  public static List<TextRange> getChangedTextRanges(@NotNull Project project, @NotNull PsiFile file) throws FilesTooBigForDiffException {
     Change change = ChangeListManager.getInstance(project).getChange(file.getVirtualFile());
     if (change == null) {
       return ContainerUtilRt.emptyList();
@@ -281,7 +281,10 @@ public class FormatChangedTextUtil {
   }
 
   @NotNull
-  private static List<TextRange> calculateChangedTextRanges(@NotNull Project project, @NotNull PsiFile file, @NotNull String contentFromVcs) {
+  private static List<TextRange> calculateChangedTextRanges(@NotNull Project project, 
+                                                            @NotNull PsiFile file, 
+                                                            @NotNull String contentFromVcs) throws FilesTooBigForDiffException 
+  {
     Document documentFromVcs = ((EditorFactoryImpl)EditorFactory.getInstance()).createDocument(contentFromVcs, true, false);
     Document document = PsiDocumentManager.getInstance(project).getDocument(file);
 
@@ -289,23 +292,16 @@ public class FormatChangedTextUtil {
       return ContainerUtil.emptyList();
     }
 
-    try {
-      List<Range> changedRanges;
-
-      LineStatusTracker tracker = LineStatusTrackerManager.getInstance(project).getLineStatusTracker(document);
-      if (tracker != null) {
-        changedRanges = tracker.getRanges();
-      }
-      else {
-        changedRanges = new RangesBuilder(document, documentFromVcs).getRanges();
-      }
-
-      return getChangedTextRanges(document, changedRanges);
+    List<Range> changedRanges;
+    LineStatusTracker tracker = LineStatusTrackerManager.getInstance(project).getLineStatusTracker(document);
+    if (tracker != null) {
+      changedRanges = tracker.getRanges();
     }
-    catch (FilesTooBigForDiffException e) {
-      LOG.error("Error while calculating changed ranges for: " + file.getVirtualFile(), e);
-      return ContainerUtil.emptyList();
+    else {
+      changedRanges = new RangesBuilder(document, documentFromVcs).getRanges();
     }
+
+    return getChangedTextRanges(document, changedRanges);
   }
 
   @NotNull
diff --git a/platform/lang-impl/src/com/intellij/codeInsight/actions/ReformatCodeProcessor.java b/platform/lang-impl/src/com/intellij/codeInsight/actions/ReformatCodeProcessor.java
index ff032c22747b..270f2f92f3cf 100644
--- a/platform/lang-impl/src/com/intellij/codeInsight/actions/ReformatCodeProcessor.java
+++ b/platform/lang-impl/src/com/intellij/codeInsight/actions/ReformatCodeProcessor.java
@@ -18,6 +18,10 @@ package com.intellij.codeInsight.actions;
 
 import com.intellij.codeInsight.CodeInsightBundle;
 import com.intellij.formatting.FormattingProgressTask;
+import com.intellij.notification.Notification;
+import com.intellij.notification.NotificationType;
+import com.intellij.openapi.application.ApplicationBundle;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.project.Project;
@@ -27,6 +31,7 @@ import com.intellij.psi.PsiFile;
 import com.intellij.psi.codeStyle.CodeStyleManager;
 import com.intellij.util.IncorrectOperationException;
 import com.intellij.util.containers.ContainerUtil;
+import com.intellij.util.diff.FilesTooBigForDiffException;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -90,6 +95,17 @@ public class ReformatCodeProcessor extends AbstractLayoutCodeProcessor {
           CodeStyleManager.getInstance(myProject).reformatText(file, ranges);
           return !FormattingProgressTask.FORMATTING_CANCELLED_FLAG.get();
         }
+        catch (FilesTooBigForDiffException e) {
+          LOG.info("Error while calculating changed ranges for: " + file.getVirtualFile(), e);
+          if (!ApplicationManager.getApplication().isUnitTestMode()) {
+            Notification notification = new Notification(ApplicationBundle.message("reformat.changed.text.file.too.big.notification.groupId"),
+                                                         ApplicationBundle.message("reformat.changed.text.file.too.big.notification.title"),
+                                                         ApplicationBundle.message("reformat.changed.text.file.too.big.notification.text", file.getName()),
+                                                         NotificationType.INFORMATION);
+            notification.notify(file.getProject());
+          }
+          return false;
+        } 
         catch (IncorrectOperationException e) {
           LOG.error(e);
           return false;
@@ -102,7 +118,7 @@ public class ReformatCodeProcessor extends AbstractLayoutCodeProcessor {
   }
 
   @NotNull
-  private Collection<TextRange> getRangesToFormat(boolean processChangedTextOnly, PsiFile file) {
+  private Collection<TextRange> getRangesToFormat(boolean processChangedTextOnly, PsiFile file) throws FilesTooBigForDiffException {
     if (processChangedTextOnly) {
       return FormatChangedTextUtil.getChangedTextRanges(myProject, file);
     }
diff --git a/platform/platform-resources-en/src/messages/ApplicationBundle.properties b/platform/platform-resources-en/src/messages/ApplicationBundle.properties
index 75d0f242e38c..053657bf7738 100644
--- a/platform/platform-resources-en/src/messages/ApplicationBundle.properties
+++ b/platform/platform-resources-en/src/messages/ApplicationBundle.properties
@@ -644,4 +644,8 @@ group.richcopy=Rich-text copy
 combobox.richcopy.color.scheme=Color scheme
 combobox.richcopy.color.scheme.active=Active scheme
 
-settings.code.style.default.general=Default (General)
\ No newline at end of file
+settings.code.style.default.general=Default (General)
+
+reformat.changed.text.file.too.big.notification.groupId=Reformat changed text
+reformat.changed.text.file.too.big.notification.title=Couldn't calculate changed ranges
+reformat.changed.text.file.too.big.notification.text=file {0} is too big or there are too many changes