diff --git a/test/api/v2/user/PUT-user.test.js b/test/api/v2/user/PUT-user.test.js
index 033a278646..e4774528ae 100644
--- a/test/api/v2/user/PUT-user.test.js
+++ b/test/api/v2/user/PUT-user.test.js
@@ -175,4 +175,27 @@ describe('PUT /user', () => {
       });
     });
   });
+
+  context('Improvement Categories', () => {
+    it('sets valid categories', async () => {
+      await user.put('/user', {
+        'preferences.improvementCategories': ['work', 'school'],
+      });
+
+      await user.sync();
+
+      expect(user.preferences.improvementCategories).to.eql(['work', 'school']);
+    });
+
+    it('discards invalid categories', async () => {
+      await expect(user.put('/user', {
+        'preferences.improvementCategories': ['work', 'procrastination', 'school'],
+      })).to.eventually.be.rejected.and.eql({
+        code: 400,
+        text: [
+          'Validator failed for path `preferences.improvementCategories` with value `work,procrastination,school`',
+        ],
+      });
+    });
+  });
 });
diff --git a/website/src/controllers/api-v2/user.js b/website/src/controllers/api-v2/user.js
index 201d1d034d..d06bb96288 100644
--- a/website/src/controllers/api-v2/user.js
+++ b/website/src/controllers/api-v2/user.js
@@ -355,7 +355,15 @@ api.update = (req, res, next) => {
 
   user.save((err) => {
     if (!_.isEmpty(errors)) return res.json(401, {err: errors});
-    if (err) return next(err);
+    if (err) {
+      if (err.name == 'ValidationError') {
+        let errorMessages = _.map(_.values(err.errors), (error) => {
+          return error.message;
+        });
+        return res.json(400, {err: errorMessages});
+      }
+      return next(err);
+    }
 
     res.json(200, user);
     user = errors = null;
diff --git a/website/src/models/user.js b/website/src/models/user.js
index d23d401f0d..9c2f11bcfd 100644
--- a/website/src/models/user.js
+++ b/website/src/models/user.js
@@ -395,7 +395,7 @@ var UserSchema = new Schema({
       type: Array,
       validate: (categories) => {
         const validCategories = ['work', 'exercise', 'healthWellness', 'school', 'teams', 'chores', 'creativity'];
-        let isValidCategory = categories.every(category => validValues.indexOf(category) !== -1);
+        let isValidCategory = categories.every(category => validCategories.indexOf(category) !== -1);
         return isValidCategory;
     }}
   },