diff --git a/app/assets/javascripts/discourse/controllers/create-account.js.es6 b/app/assets/javascripts/discourse/controllers/create-account.js.es6
index a3d4ef4aa47..d04a03821c6 100644
--- a/app/assets/javascripts/discourse/controllers/create-account.js.es6
+++ b/app/assets/javascripts/discourse/controllers/create-account.js.es6
@@ -31,7 +31,6 @@ export default Ember.Controller.extend(ModalFunctionality, PasswordValidation, U
       accountUsername: '',
       accountPassword: '',
       authOptions: null,
-      globalNicknameExists: false,
       complete: false,
       formSubmitted: false,
       rejectedEmails: [],
diff --git a/app/assets/javascripts/discourse/mixins/username-validation.js.es6 b/app/assets/javascripts/discourse/mixins/username-validation.js.es6
index 1bbf64d9f23..91e9554c9ff 100644
--- a/app/assets/javascripts/discourse/mixins/username-validation.js.es6
+++ b/app/assets/javascripts/discourse/mixins/username-validation.js.es6
@@ -1,11 +1,11 @@
 import InputValidation from 'discourse/models/input-validation';
 import debounce from 'discourse/lib/debounce';
 import { setting } from 'discourse/lib/computed';
+import { default as computed } from 'ember-addons/ember-computed-decorators';
 
 export default Ember.Mixin.create({
 
   uniqueUsernameValidation: null,
-  globalNicknameExists: false, // TODO: remove this
 
   maxUsernameLength: setting('max_username_length'),
   minUsernameLength: setting('min_username_length'),
@@ -20,31 +20,12 @@ export default Ember.Mixin.create({
     });
   }, 500),
 
-  usernameMatch: function() {
-    if (this.usernameNeedsToBeValidatedWithEmail()) {
-      if (this.get('emailValidation.failed')) {
-        if (this.shouldCheckUsernameMatch()) {
-          return this.set('uniqueUsernameValidation', InputValidation.create({
-            failed: true,
-            reason: I18n.t('user.username.enter_email')
-          }));
-        } else {
-          return this.set('uniqueUsernameValidation', InputValidation.create({ failed: true }));
-        }
-      } else if (this.shouldCheckUsernameMatch()) {
-        this.set('uniqueUsernameValidation', InputValidation.create({
-          failed: true,
-          reason: I18n.t('user.username.checking')
-        }));
-        return this.checkUsernameAvailability();
-      }
-    }
-  }.observes('accountEmail'),
-
-  basicUsernameValidation: function() {
+  @computed('accountUsername')
+  basicUsernameValidation(accountUsername) {
     this.set('uniqueUsernameValidation', null);
 
-    if (this.get('accountUsername') === this.get('prefilledUsername')) {
+
+    if (accountUsername === this.get('prefilledUsername')) {
       return InputValidation.create({
         ok: true,
         reason: I18n.t('user.username.prefilled')
@@ -52,14 +33,14 @@ export default Ember.Mixin.create({
     }
 
     // If blank, fail without a reason
-    if (Ember.isEmpty(this.get('accountUsername'))) {
+    if (Ember.isEmpty(accountUsername)) {
       return InputValidation.create({
         failed: true
       });
     }
 
     // If too short
-    if (this.get('accountUsername').length < Discourse.SiteSettings.min_username_length) {
+    if (accountUsername.length < Discourse.SiteSettings.min_username_length) {
       return InputValidation.create({
         failed: true,
         reason: I18n.t('user.username.too_short')
@@ -67,7 +48,7 @@ export default Ember.Mixin.create({
     }
 
     // If too long
-    if (this.get('accountUsername').length > this.get('maxUsernameLength')) {
+    if (accountUsername.length > this.get('maxUsernameLength')) {
       return InputValidation.create({
         failed: true,
         reason: I18n.t('user.username.too_long')
@@ -80,40 +61,34 @@ export default Ember.Mixin.create({
       failed: true,
       reason: I18n.t('user.username.checking')
     });
-  }.property('accountUsername'),
+  },
 
-  shouldCheckUsernameMatch: function() {
+  shouldCheckUsernameAvailability: function() {
     return !Ember.isEmpty(this.get('accountUsername')) && this.get('accountUsername').length >= this.get('minUsernameLength');
   },
 
   checkUsernameAvailability: debounce(function() {
-    const _this = this;
-    if (this.shouldCheckUsernameMatch()) {
-      return Discourse.User.checkUsername(this.get('accountUsername'), this.get('accountEmail')).then(function(result) {
-        _this.set('isDeveloper', false);
+    if (this.shouldCheckUsernameAvailability()) {
+      return Discourse.User.checkUsername(this.get('accountUsername'), this.get('accountEmail')).then(result => {
+        this.set('isDeveloper', false);
         if (result.available) {
           if (result.is_developer) {
-            _this.set('isDeveloper', true);
+            this.set('isDeveloper', true);
           }
-          return _this.set('uniqueUsernameValidation', InputValidation.create({
+          return this.set('uniqueUsernameValidation', InputValidation.create({
             ok: true,
             reason: I18n.t('user.username.available')
           }));
         } else {
           if (result.suggestion) {
-            return _this.set('uniqueUsernameValidation', InputValidation.create({
+            return this.set('uniqueUsernameValidation', InputValidation.create({
               failed: true,
               reason: I18n.t('user.username.not_available', result)
             }));
-          } else if (result.errors) {
-            return _this.set('uniqueUsernameValidation', InputValidation.create({
-              failed: true,
-              reason: result.errors.join(' ')
-            }));
           } else {
-            return _this.set('uniqueUsernameValidation', InputValidation.create({
+            return this.set('uniqueUsernameValidation', InputValidation.create({
               failed: true,
-              reason: I18n.t('user.username.enter_email')
+              reason: result.errors ? result.errors.join(' ') : I18n.t('user.username.not_available_no_suggestion')
             }));
           }
         }
@@ -122,13 +97,10 @@ export default Ember.Mixin.create({
   }, 500),
 
   // Actually wait for the async name check before we're 100% sure we're good to go
-  usernameValidation: function() {
+  @computed('uniqueUsernameValidation', 'basicUsernameValidation')
+  usernameValidation() {
     const basicValidation = this.get('basicUsernameValidation');
     const uniqueUsername = this.get('uniqueUsernameValidation');
     return uniqueUsername ? uniqueUsername : basicValidation;
-  }.property('uniqueUsernameValidation', 'basicUsernameValidation'),
-
-  usernameNeedsToBeValidatedWithEmail() {
-    return( this.get('globalNicknameExists') || false );
   }
 });
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index d59dc5cbbc9..b00207e7a9c 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -718,13 +718,11 @@ en:
         instructions: "unique, no spaces, short"
         short_instructions: "People can mention you as @{{username}}"
         available: "Your username is available"
-        global_match: "Email matches the registered username"
-        global_mismatch: "Already registered. Try {{suggestion}}?"
         not_available: "Not available. Try {{suggestion}}?"
+        not_available_no_suggestion: "Not available"
         too_short: "Your username is too short"
         too_long: "Your username is too long"
         checking: "Checking username availability..."
-        enter_email: 'Username found; enter matching email'
         prefilled: "Email matches this registered username"
 
       locale: