diff --git a/src/server/saved_objects/migrations/core/call_cluster.ts b/src/server/saved_objects/migrations/core/call_cluster.ts
index e9533691d34f2..20dc640b1a291 100644
--- a/src/server/saved_objects/migrations/core/call_cluster.ts
+++ b/src/server/saved_objects/migrations/core/call_cluster.ts
@@ -41,7 +41,10 @@ export interface CallCluster {
   (path: 'reindex', opts: ReindexOpts): Promise<any>;
   (path: 'scroll', opts: ScrollOpts): Promise<SearchResults>;
   (path: 'search', opts: SearchOpts): Promise<SearchResults>;
-  (path: 'tasks.get', opts: { taskId: string }): Promise<{ completed: boolean }>;
+  (path: 'tasks.get', opts: { taskId: string }): Promise<{
+    completed: boolean;
+    error?: ErrorResponse;
+  }>;
 }
 
 ///////////////////////////////////////////////////////////////////
@@ -171,8 +174,13 @@ export interface SearchResults {
   _scroll_id?: string;
 }
 
+export interface ErrorResponse {
+  type: string;
+  reason: string;
+}
+
 export interface BulkResult {
-  items: Array<{ index: { error?: { type: string; reason: string } } }>;
+  items: Array<{ index: { error?: ErrorResponse } }>;
 }
 
 export interface IndexInfo {
diff --git a/src/server/saved_objects/migrations/core/elastic_index.test.ts b/src/server/saved_objects/migrations/core/elastic_index.test.ts
index e2a27e7523aa8..e152516d4cfe7 100644
--- a/src/server/saved_objects/migrations/core/elastic_index.test.ts
+++ b/src/server/saved_objects/migrations/core/elastic_index.test.ts
@@ -309,6 +309,68 @@ describe('ElasticIndex', () => {
         'indices.refresh',
       ]);
     });
+
+    test('throws error if re-index task fails', async () => {
+      const callCluster = sinon.spy(async (path: string, arg: any) => {
+        switch (path) {
+          case 'indices.create':
+            expect(arg.body).toEqual({
+              mappings: {
+                doc: {
+                  dynamic: 'strict',
+                  properties: { foo: 'bar' },
+                },
+              },
+              settings: { auto_expand_replicas: '0-1', number_of_shards: 1 },
+            });
+            expect(arg.index).toEqual('.ze-index');
+            return true;
+          case 'reindex':
+            expect(arg).toMatchObject({
+              body: {
+                dest: { index: '.ze-index' },
+                source: { index: '.muchacha' },
+              },
+              refresh: true,
+              waitForCompletion: false,
+            });
+            return { task: 'abc' };
+          case 'tasks.get':
+            expect(arg.taskId).toEqual('abc');
+            return {
+              completed: true,
+              error: {
+                type: 'search_phase_execution_exception',
+                reason: 'all shards failed',
+                failed_shards: [],
+              },
+            };
+          default:
+            throw new Error(`Dunnoes what ${path} means.`);
+        }
+      });
+
+      const info = {
+        aliases: {},
+        exists: true,
+        indexName: '.ze-index',
+        mappings: {
+          doc: {
+            dynamic: 'strict',
+            properties: { foo: 'bar' },
+          },
+        },
+      };
+      await expect(Index.convertToAlias(callCluster, info, '.muchacha', 10)).rejects.toThrow(
+        /Re-index failed \[search_phase_execution_exception\] all shards failed/
+      );
+
+      expect(callCluster.args.map(([path]) => path)).toEqual([
+        'indices.create',
+        'reindex',
+        'tasks.get',
+      ]);
+    });
   });
 
   describe('write', () => {
diff --git a/src/server/saved_objects/migrations/core/elastic_index.ts b/src/server/saved_objects/migrations/core/elastic_index.ts
index 8e21964c7d376..3a881b2a594fa 100644
--- a/src/server/saved_objects/migrations/core/elastic_index.ts
+++ b/src/server/saved_objects/migrations/core/elastic_index.ts
@@ -322,6 +322,13 @@ async function reindex(callCluster: CallCluster, source: string, dest: string, b
 
     completed = await callCluster('tasks.get', {
       taskId: task,
-    }).then(result => result.completed);
+    }).then(result => {
+      if (result.error) {
+        const e = result.error;
+        throw new Error(`Re-index failed [${e.type}] ${e.reason} :: ${JSON.stringify(e)}`);
+      }
+
+      return result.completed;
+    });
   }
 }