Update to Drupal 8.2.4. For more information, see https://www.drupal.org/project/drupal/releases/8.2.4

core/modules/user/migration_templates/d6_user.yml

@@ -5,6 +5,8 @@ migration_tags:
 source:
   plugin: d6_user
 process:
+  # If you are using this file to build a custom migration consider removing
+  # the uid field to allow incremental migrations.
   uid: uid
   name: name
   pass: pass

core/modules/user/migration_templates/d6_user_picture_file.yml

@@ -11,6 +11,9 @@ source:
     # table are specified, and must end with a /.
     source_base_path: ''
 process:
+    # If you are using both this migration and d6_file in a custom migration
+    # and executing migrations incrementally, it is recommended that you
+    # remove the fid mapping from d6_file to avoid potential ID conflicts.
   filename: filename
   uid: uid
   source_full_path:

core/modules/user/migration_templates/d7_user.yml

@@ -6,6 +6,8 @@ class: Drupal\user\Plugin\migrate\User
 source:
   plugin: d7_user
 process:
+  # If you are using this file to build a custom migration consider removing
+  # the uid field to allow incremental migrations.
   uid: uid
   name: name
   pass: pass

core/modules/user/migration_templates/user_picture_field.yml

@@ -18,4 +18,7 @@ process:
   type: 'constants/type'
   cardinality: 'constants/cardinality'
 destination:
-  plugin: md_entity:field_storage_config
+  plugin: entity:field_storage_config
+  dependencies:
+    module:
+      - image

core/modules/user/migration_templates/user_profile_field.yml

@@ -32,4 +32,4 @@ process:
     map:
       list: -1
 destination:
-  plugin: md_entity:field_storage_config
+  plugin: entity:field_storage_config