diff --git a/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/Snapshot.java b/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/Snapshot.java
index 2272b97..732cadb 100644
--- a/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/Snapshot.java
+++ b/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/Snapshot.java
@@ -34,14 +34,14 @@
 
 public class Snapshot implements Watcher {
     static final SimpleDateFormat DATE_FORMAT_SNAPSHOT = new SimpleDateFormat("yyyyMMddHHmmss");
+    static final int ABORT_ZNODE_AGE_THRESHOLD_MS = 24 * 60 * 60 * 1000;
+    static final String TIMESTAMP_PREFIX = "_S";
     private static final int SESSION_TIMEOUT = 120000;
     private static final SimpleDateFormat DATE_FORMAT_LOG = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
     private static final String ABORT_WATCH_PREFIX = "/hbase/online-snapshot/abort/";
     private static final String ACQUIRED_WATCH_PREFIX = "/hbase/online-snapshot/acquired/";
-    private static final String TIMESTAMP_PREFIX = "_S";
     private static final int MAX_RETRY = 10;
     private static final long RETRY_INTERVAL = 2000;
-    private static final int ABORT_ZNODE_AGE_THRESHOLD_MS = 24 * 60 * 60 * 1000;
     @VisibleForTesting
     static boolean skipCheckTableExistence = false;
     private final SnapshotArgs args;
@@ -159,8 +159,7 @@ private void deleteOldAbortZnodes(ZooKeeper zooKeeper) throws KeeperException, I
         String parentZnode = ABORT_WATCH_PREFIX.substring(0, ABORT_WATCH_PREFIX.length() - 1);
         List<String> children = zooKeeper.getChildren(parentZnode, false);
         for (String snapshotName : children) {
-            long abortZnodeAge = System.currentTimeMillis() - SnapshotUtil.getSnapshotTimestamp(snapshotName);
-            if (abortZnodeAge > ABORT_ZNODE_AGE_THRESHOLD_MS) {
+            if (SnapshotUtil.isOldZnode(snapshotName)) {
                 String abortZnode = ABORT_WATCH_PREFIX + snapshotName;
                 System.out.println(timestamp(TimestampFormat.log) + " - znode deleted - " + abortZnode);
                 zooKeeper.delete(abortZnode, -1);
diff --git a/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/SnapshotUtil.java b/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/SnapshotUtil.java
index 96d5e5e..7faf575 100644
--- a/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/SnapshotUtil.java
+++ b/hbase0.98/hbase-snapshot-0.98/src/main/java/com/kakao/hbase/snapshot/SnapshotUtil.java
@@ -3,9 +3,21 @@
 public class SnapshotUtil {
     static long getSnapshotTimestamp(String snapshotName) {
         try {
-            return Snapshot.DATE_FORMAT_SNAPSHOT.parse(snapshotName.substring(snapshotName.length() - 14)).getTime();
+            String suffix = snapshotName.substring(snapshotName.length() - 16);
+            if (suffix.startsWith(Snapshot.TIMESTAMP_PREFIX)) {
+                return Snapshot.DATE_FORMAT_SNAPSHOT.parse(suffix.substring(2)).getTime();
+            } else {
+                // invalid snapshot name format
+                return 0;
+            }
         } catch (Throwable e) {
+            // invalid snapshot name format
             return 0;
         }
     }
+
+    static boolean isOldZnode(String snapshotName) {
+        long abortZnodeAge = System.currentTimeMillis() - getSnapshotTimestamp(snapshotName);
+        return getSnapshotTimestamp(snapshotName) > 0 && abortZnodeAge > Snapshot.ABORT_ZNODE_AGE_THRESHOLD_MS;
+    }
 }
diff --git a/hbase0.98/hbase-snapshot-0.98/src/test/java/com/kakao/hbase/snapshot/SnapshotUtilTest.java b/hbase0.98/hbase-snapshot-0.98/src/test/java/com/kakao/hbase/snapshot/SnapshotUtilTest.java
index c9590a0..131f21b 100644
--- a/hbase0.98/hbase-snapshot-0.98/src/test/java/com/kakao/hbase/snapshot/SnapshotUtilTest.java
+++ b/hbase0.98/hbase-snapshot-0.98/src/test/java/com/kakao/hbase/snapshot/SnapshotUtilTest.java
@@ -16,4 +16,10 @@ public void testGetSnapshotTimestamp() throws ParseException {
         Assert.assertEquals(date.getTime(), snapshotTimestamp);
         Assert.assertEquals(timestampMS, snapshotTimestamp);
     }
+
+    @Test
+    public void testInvalidSnapshotName() {
+        Assert.assertTrue(SnapshotUtil.isOldZnode("valid-snapshot-name_S20000309110025"));
+        Assert.assertFalse(SnapshotUtil.isOldZnode("invalid-snapshot-name"));
+    }
 }