diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsPackFile.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsPackFile.java
index ed6628596..80cced84e 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsPackFile.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/dfs/DfsPackFile.java
@@ -277,6 +277,8 @@ else if (bs <= 0)
 	}
 
 	PackBitmapIndex getBitmapIndex(DfsReader ctx) throws IOException {
+		if (invalid)
+			return null;
 		DfsBlockCache.Ref<PackBitmapIndex> idxref = bitmapIndex;
 		if (idxref != null) {
 			PackBitmapIndex idx = idxref.get();
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/PackFile.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/PackFile.java
index 31de38172..cd5de595c 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/PackFile.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/PackFile.java
@@ -1057,6 +1057,8 @@ private long findEndOffset(final long startOffset)
 	}
 
 	synchronized PackBitmapIndex getBitmapIndex() throws IOException {
+		if (invalid)
+			return null;
 		if (bitmapIdx == null && hasExt(BITMAP_INDEX)) {
 			final PackBitmapIndex idx = PackBitmapIndex.open(
 					extFile(BITMAP_INDEX), idx(), getReverseIdx());