diff --git a/lib/database/adapters/UserAdapter.js b/lib/database/adapters/UserAdapter.js
index 38e3e87ea8..15ef006ab8 100644
--- a/lib/database/adapters/UserAdapter.js
+++ b/lib/database/adapters/UserAdapter.js
@@ -21,8 +21,20 @@ class UserAdapter {
      * @param {Object} databaseObject Object to convert.
      * @returns {Object} Converted entity object.
      */
-    static toEntity({ id, externalId, name }) {
-        return { id, externalId, name };
+    static toEntity(databaseObject) {
+        if (databaseObject) {
+            return {
+                id: databaseObject.id,
+                externalId: databaseObject.externalId,
+                name: databaseObject.name,
+            };
+        } else {
+            return {
+                id: 0,
+                externalId: 0,
+                name: 'Anonymous',
+            };
+        }
     }
 
     /**
diff --git a/lib/database/migrations/20200914120527-logs-remove-user-constraint.js b/lib/database/migrations/20200914120527-logs-remove-user-constraint.js
new file mode 100644
index 0000000000..e98dfd1e18
--- /dev/null
+++ b/lib/database/migrations/20200914120527-logs-remove-user-constraint.js
@@ -0,0 +1,25 @@
+/**
+ * @license
+ * Copyright CERN and copyright holders of ALICE O2. This software is
+ * distributed under the terms of the GNU General Public License v3 (GPL
+ * Version 3), copied verbatim in the file "COPYING".
+ *
+ * See http://alice-o2.web.cern.ch/license for full licensing information.
+ *
+ * In applying this license CERN does not waive the privileges and immunities
+ * granted to it by virtue of its status as an Intergovernmental Organization
+ * or submit itself to any jurisdiction.
+ */
+
+module.exports = {
+    up: (queryInterface, Sequelize) => queryInterface.changeColumn('logs', 'user_id', {
+        type: Sequelize.INTEGER,
+        allowNull: true,
+    }),
+
+    down: (queryInterface, Sequelize) => queryInterface.changeColumn('logs', 'user_id', {
+        type: Sequelize.INTEGER,
+        allowNull: false,
+    }),
+
+};
diff --git a/lib/database/seeders/20200508094502-logs.js b/lib/database/seeders/20200508094502-logs.js
index 32b08f9c05..f0e5df0b44 100644
--- a/lib/database/seeders/20200508094502-logs.js
+++ b/lib/database/seeders/20200508094502-logs.js
@@ -35,7 +35,6 @@ module.exports = {
             title: 'Third entry',
             subtype: 'announcement',
             origin: 'human',
-            user_id: 1,
             text: 'Cake at the particle accelerator!',
             parent_log_id: 1,
             root_log_id: 1,
diff --git a/lib/public/components/Post/index.js b/lib/public/components/Post/index.js
index 3db36d5d84..6f2063d6bd 100644
--- a/lib/public/components/Post/index.js
+++ b/lib/public/components/Post/index.js
@@ -60,7 +60,6 @@ const activeFields = (model) => ({
         name: 'Tags',
         visible: true,
         format: (tags) => tags.length > 0 ? tags.map(({ text }) => text).join(', ') : 'None',
-
     },
     runs: {
         name: 'Runs',
@@ -115,7 +114,7 @@ const entry = (model, post, index, highlight) => {
                 h('tbody', Object.entries(postFields)
                     .map(([key, { name, format, visible }]) => visible && h(`tr#post${index}-${key}`, [
                         h('td.text-right', { style: 'font-weight: bold' }, `${name}:`),
-                        h('td', post[key] && format ? format(post[key]) : post[key] || 'None'),
+                        h('td', format ? format(post[key]) : post[key]),
                     ]))),
             ]),
         ]),
diff --git a/lib/usecases/log/CreateLogUseCase.js b/lib/usecases/log/CreateLogUseCase.js
index 5e55371c21..3657ac24aa 100644
--- a/lib/usecases/log/CreateLogUseCase.js
+++ b/lib/usecases/log/CreateLogUseCase.js
@@ -46,7 +46,7 @@ class CreateLogUseCase {
         const { parentLogId, tags } = body;
 
         const log = await TransactionHelper.provide(async () => {
-            body.userId = dto.session.id;
+            body.userId = dto.session.id || null;
 
             if (parentLogId) {
                 const parentLog = await new GetLogUseCase().execute({ params: { logId: parentLogId } });
diff --git a/spec/openapi-source.yaml b/spec/openapi-source.yaml
index 319f926603..b7b9d12957 100644
--- a/spec/openapi-source.yaml
+++ b/spec/openapi-source.yaml
@@ -1196,19 +1196,24 @@ components:
       additionalProperties: false
     User:
       allOf:
-        - $ref: '#/components/schemas/Entity'
         - description: Describes an intervention or an event that happened.
           type: object
           properties:
+            id:
+              description: The unique identifier of this entity.
+              type: integer
+              format: int64
+              minimum: 0
             externalId:
               description: The unique CERN identifier of this user.
               type: integer
               format: int64
-              minimum: 1
+              minimum: 0
             name:
               type: string
               description: Name of the user.
           required:
+            - id
             - externalId
             - name
           additionalProperties: false
diff --git a/spec/openapi.yaml b/spec/openapi.yaml
index 1d2d6ec5f0..a0468c7193 100644
--- a/spec/openapi.yaml
+++ b/spec/openapi.yaml
@@ -1,4 +1,4 @@
-# Generated on Sun, 30 Aug 2020 09:11:14 GMT
+# Generated on Mon, 14 Sep 2020 22:40:53 GMT
 
 openapi: 3.0.0
 info:
@@ -1342,24 +1342,19 @@ components:
       description: Describes an intervention or an event that happened.
       type: object
       properties:
-        createdAt:
-          description: Unix timestamp when this entity was created.
-          type: integer
-          format: int64
         externalId:
           description: The unique CERN identifier of this user.
           type: integer
           format: int64
-          minimum: 1
+          minimum: 0
         id:
-          $ref: '#/components/schemas/EntityId'
+          description: The unique identifier of this entity.
+          type: integer
+          format: int64
+          minimum: 0
         name:
           type: string
           description: Name of the user.
-        updatedAt:
-          description: Unix timestamp when this entity was last updated.
-          type: integer
-          format: int64
       required:
         - externalId
         - id