diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index dcf701dd95a..515ded4f7ab 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -558,6 +558,10 @@ Release 0.23.5 - UNRELEASED
     MAPREDUCE-4554. Job Credentials are not transmitted if security is turned 
     off (Benoy Antony via bobby)
 
+    MAPREDUCE-4705. Fix a bug in job history lookup, which makes older jobs
+    inaccessible despite the presence of a valid history file. (Jason Lowe
+    via sseth)
+
 Release 0.23.4 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/HistoryFileManager.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/HistoryFileManager.java
index 85fcdc6bd5a..f7bc50609ab 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/HistoryFileManager.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/HistoryFileManager.java
@@ -62,6 +62,7 @@ import org.apache.hadoop.mapreduce.v2.jobhistory.JobIndexInfo;
 import org.apache.hadoop.yarn.YarnException;
 import org.apache.hadoop.yarn.service.AbstractService;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 
 /**
@@ -130,7 +131,7 @@ public class HistoryFileManager extends AbstractService {
     }
   }
 
-  private static class JobListCache {
+  static class JobListCache {
     private ConcurrentSkipListMap<JobId, HistoryFileInfo> cache;
     private int maxSize;
     private long maxAge;
@@ -239,12 +240,14 @@ public class HistoryFileManager extends AbstractService {
           : HistoryInfoState.IN_INTERMEDIATE;
     }
 
-    private synchronized boolean isMovePending() {
+    @VisibleForTesting
+    synchronized boolean isMovePending() {
       return state == HistoryInfoState.IN_INTERMEDIATE
           || state == HistoryInfoState.MOVE_FAILED;
     }
 
-    private synchronized boolean didMoveFail() {
+    @VisibleForTesting
+    synchronized boolean didMoveFail() {
       return state == HistoryInfoState.MOVE_FAILED;
     }
     
@@ -365,7 +368,7 @@ public class HistoryFileManager extends AbstractService {
   }
 
   private SerialNumberIndex serialNumberIndex = null;
-  private JobListCache jobListCache = null;
+  protected JobListCache jobListCache = null;
 
   // Maintains a list of known done subdirectories.
   private final Set<Path> existingDoneSubdirs = Collections
@@ -707,8 +710,8 @@ public class HistoryFileManager extends AbstractService {
    * @throws IOException
    */
   private HistoryFileInfo scanOldDirsForJob(JobId jobId) throws IOException {
-    int jobSerialNumber = JobHistoryUtils.jobSerialNumber(jobId);
-    String boxedSerialNumber = String.valueOf(jobSerialNumber);
+    String boxedSerialNumber = JobHistoryUtils.serialNumberDirectoryComponent(
+        jobId, serialNumberFormat);
     Set<String> dateStringSet = serialNumberIndex.get(boxedSerialNumber);
     if (dateStringSet == null) {
       return null;
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/TestJobHistoryParsing.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/TestJobHistoryParsing.java
index f9acb1a3821..e24cf05d790 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/TestJobHistoryParsing.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/test/java/org/apache/hadoop/mapreduce/v2/hs/TestJobHistoryParsing.java
@@ -60,6 +60,7 @@ import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptEventType;
 import org.apache.hadoop.mapreduce.v2.hs.HistoryFileManager.HistoryFileInfo;
 import org.apache.hadoop.mapreduce.v2.hs.TestJobHistoryEvents.MRAppWithHistory;
 import org.apache.hadoop.mapreduce.v2.jobhistory.FileNameIndexUtils;
+import org.apache.hadoop.mapreduce.v2.jobhistory.JHAdminConfig;
 import org.apache.hadoop.mapreduce.v2.jobhistory.JobHistoryUtils;
 import org.apache.hadoop.mapreduce.v2.jobhistory.JobIndexInfo;
 import org.apache.hadoop.net.DNSToSwitchMapping;
@@ -460,6 +461,51 @@ public class TestJobHistoryParsing {
     }
   }
 
+  @Test
+  public void testScanningOldDirs() throws Exception {
+    LOG.info("STARTING testScanningOldDirs");
+    try {
+    Configuration conf = new Configuration();
+    conf
+        .setClass(
+            CommonConfigurationKeysPublic.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY,
+            MyResolver.class, DNSToSwitchMapping.class);
+    RackResolver.init(conf);
+    MRApp app =
+        new MRAppWithHistory(1, 1, true,
+            this.getClass().getName(), true);
+    app.submit(conf);
+    Job job = app.getContext().getAllJobs().values().iterator().next();
+    JobId jobId = job.getID();
+    LOG.info("JOBID is " + TypeConverter.fromYarn(jobId).toString());
+    app.waitForState(job, JobState.SUCCEEDED);
+
+    // make sure all events are flushed
+    app.waitForState(Service.STATE.STOPPED);
+
+    HistoryFileManagerForTest hfm = new HistoryFileManagerForTest();
+    hfm.init(conf);
+    HistoryFileInfo fileInfo = hfm.getFileInfo(jobId);
+    Assert.assertNotNull("Unable to locate job history", fileInfo);
+
+    // force the manager to "forget" the job
+    hfm.deleteJobFromJobListCache(fileInfo);
+    final int msecPerSleep = 10;
+    int msecToSleep = 10 * 1000;
+    while (fileInfo.isMovePending() && msecToSleep > 0) {
+      Assert.assertTrue(!fileInfo.didMoveFail());
+      msecToSleep -= msecPerSleep;
+      Thread.sleep(msecPerSleep);
+    }
+    Assert.assertTrue("Timeout waiting for history move", msecToSleep > 0);
+
+    fileInfo = hfm.getFileInfo(jobId);
+    Assert.assertNotNull("Unable to locate old job history", fileInfo);
+   } finally {
+      LOG.info("FINISHED testScanningOldDirs");
+    }
+  }
+
   static class MRAppWithHistoryWithFailedAttempt extends MRAppWithHistory {
 
     public MRAppWithHistoryWithFailedAttempt(int maps, int reduces, boolean autoComplete,
@@ -500,6 +546,12 @@ public class TestJobHistoryParsing {
     }
   }
 
+  static class HistoryFileManagerForTest extends HistoryFileManager {
+    void deleteJobFromJobListCache(HistoryFileInfo fileInfo) {
+      jobListCache.delete(fileInfo);
+    }
+  }
+
   public static void main(String[] args) throws Exception {
     TestJobHistoryParsing t = new TestJobHistoryParsing();
     t.testHistoryParsing();