diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java
index 6489415eb..44ad99bb9 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/ObjectDirectory.java
@@ -820,13 +820,13 @@ private PackList scanPacksImpl(final PackList old) {
 			}
 
 			final String packName = base + PACK.getExtension();
+			final File packFile = new File(packDirectory, packName);
 			final PackFile oldPack = forReuse.remove(packName);
-			if (oldPack != null) {
+			if (oldPack != null && oldPack.getFileSnapshot().isModified(packFile)) {
 				list.add(oldPack);
 				continue;
 			}
 
-			final File packFile = new File(packDirectory, packName);
 			list.add(new PackFile(packFile, extensions));
 			foundNew = true;
 		}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java
index b5889f2dd..9a1d12f40 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackFile.java
@@ -129,6 +129,8 @@ public int compare(final PackFile a, final PackFile b) {
 
 	int packLastModified;
 
+	private FileSnapshot fileSnapshot;
+
 	private volatile boolean invalid;
 
 	private boolean invalidBitmap;
@@ -163,6 +165,7 @@ public int compare(final PackFile a, final PackFile b) {
 	public PackFile(final File packFile, int extensions) {
 		this.packFile = packFile;
 		this.packLastModified = (int) (packFile.lastModified() >> 10);
+		this.fileSnapshot = FileSnapshot.save(packFile);
 		this.extensions = extensions;
 
 		// Multiply by 31 here so we can more directly combine with another
@@ -335,6 +338,16 @@ ObjectId findObjectForOffset(final long offset) throws IOException {
 		return getReverseIdx().findObject(offset);
 	}
 
+	/**
+	 * Return the @{@link FileSnapshot} associated to the underlying packfile
+	 * that has been used when the object was created.
+	 *
+	 * @return the packfile @{@link FileSnapshot} that the object is loaded from.
+	 */
+	FileSnapshot getFileSnapshot() {
+		return fileSnapshot;
+	}
+
 	private final byte[] decompress(final long position, final int sz,
 			final WindowCursor curs) throws IOException, DataFormatException {
 		byte[] dstbuf;