diff --git a/core/src/main/scala/org/apache/spark/SparkEnv.scala b/core/src/main/scala/org/apache/spark/SparkEnv.scala
index f8b7cdcf7a8b0..6b7fc1b0804b7 100644
--- a/core/src/main/scala/org/apache/spark/SparkEnv.scala
+++ b/core/src/main/scala/org/apache/spark/SparkEnv.scala
@@ -73,7 +73,7 @@ class SparkEnv (
 
   // We initialize the ShuffleManager later in SparkContext and Executor to allow
   // user jars to define custom ShuffleManagers.
-  private var _shuffleManager: ShuffleManager = _
+  @volatile private var _shuffleManager: ShuffleManager = _
 
   def shuffleManager: ShuffleManager = _shuffleManager
 
diff --git a/core/src/main/scala/org/apache/spark/storage/BlockManagerStorageEndpoint.scala b/core/src/main/scala/org/apache/spark/storage/BlockManagerStorageEndpoint.scala
index 686ac1eb786e0..f29e8778da037 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockManagerStorageEndpoint.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManagerStorageEndpoint.scala
@@ -60,7 +60,13 @@ class BlockManagerStorageEndpoint(
         if (mapOutputTracker != null) {
           mapOutputTracker.unregisterShuffle(shuffleId)
         }
-        SparkEnv.get.shuffleManager.unregisterShuffle(shuffleId)
+        val shuffleManager = SparkEnv.get.shuffleManager
+        if (shuffleManager != null) {
+          shuffleManager.unregisterShuffle(shuffleId)
+        } else {
+          logDebug(log"Ignore remove shuffle ${MDC(SHUFFLE_ID, shuffleId)}")
+          true
+        }
       }
 
     case DecommissionBlockManager =>