diff --git a/core/src/main/java/org/bitcoinj/kits/WalletAppKit.java b/core/src/main/java/org/bitcoinj/kits/WalletAppKit.java
index a7d6169f8..903e97a71 100644
--- a/core/src/main/java/org/bitcoinj/kits/WalletAppKit.java
+++ b/core/src/main/java/org/bitcoinj/kits/WalletAppKit.java
@@ -238,7 +238,7 @@ public class WalletAppKit extends AbstractIdleService {
     /**
      * Tests to see if the spvchain file has an operating system file lock on it. Useful for checking if your app
      * is already running. If another copy of your app is running and you start the appkit anyway, an exception will
-     * be thrown during the startup process. Returns false if the chain file does not exist.
+     * be thrown during the startup process. Returns false if the chain file does not exist or is a directory.
      */
     public boolean isChainFileLocked() throws IOException {
         RandomAccessFile file2 = null;
@@ -246,6 +246,8 @@ public class WalletAppKit extends AbstractIdleService {
             File file = new File(directory, filePrefix + ".spvchain");
             if (!file.exists())
                 return false;
+            if (file.isDirectory())
+                return false;
             file2 = new RandomAccessFile(file, "rw");
             FileLock lock = file2.getChannel().tryLock();
             if (lock == null)
diff --git a/core/src/main/java/org/bitcoinj/store/LevelDBBlockStore.java b/core/src/main/java/org/bitcoinj/store/LevelDBBlockStore.java
index e8dfba184..d21d4d146 100644
--- a/core/src/main/java/org/bitcoinj/store/LevelDBBlockStore.java
+++ b/core/src/main/java/org/bitcoinj/store/LevelDBBlockStore.java
@@ -18,7 +18,7 @@ public class LevelDBBlockStore implements BlockStore {
     private static final byte[] CHAIN_HEAD_KEY = "chainhead".getBytes();
 
     private final Context context;
-    private final DB db;
+    private DB db;
     private final ByteBuffer buffer = ByteBuffer.allocate(StoredBlock.COMPACT_SERIALIZED_SIZE);
     private final File path;
 
@@ -35,14 +35,23 @@ public class LevelDBBlockStore implements BlockStore {
         options.createIfMissing();
 
         try {
-            db = dbFactory.open(directory, options);
-            initStoreIfNeeded();
+            tryOpen(directory, dbFactory, options);
         } catch (IOException e) {
-            throw new BlockStoreException(e);
+            try {
+                dbFactory.repair(directory, options);
+                tryOpen(directory, dbFactory, options);
+            } catch (IOException e1) {
+                throw new BlockStoreException(e1);
+            }
         }
     }
 
-    private void initStoreIfNeeded() throws BlockStoreException {
+    private synchronized void tryOpen(File directory, DBFactory dbFactory, Options options) throws IOException, BlockStoreException {
+        db = dbFactory.open(directory, options);
+        initStoreIfNeeded();
+    }
+
+    private synchronized void initStoreIfNeeded() throws BlockStoreException {
         if (db.get(CHAIN_HEAD_KEY) != null)
             return;   // Already initialised.
         Block genesis = context.getParams().getGenesisBlock().cloneAsHeader();